The mkII protoype fits nicely! Now, I have only test fit the wheel and not the airbag, horn connections etc. but here's what I know about what's required to fit these. I'll assume you've already followed the procedure for disarming the airbag system and removed the stock wheel. Removing the knee bolster also helps.
UPDATED (v2) 1. The Elise contact ring (or idential GM part sourced from a Vauxhall, etc.) is used only for the connector plugs. Cut off the 2 connectors that are used to plug into the back of the airbag and hook up all the horn wiring.
2. HORN: The stock horn connections use one wire (spliced inside the steering wheel connector to run to 2 horn buttons) for power with the ground wire attached inside the steering wheel body to a ground point. All this you can see when you remove the stock wheel and airbag. Firstly, cut off the stock horn connector from inside the stock wheel as you will want to use this to mate with the stock contact ring. I'd much rather mess with this connector than be modifying the contact ring as the connector can easily be spliced back onto the stock wheel if required. Be sure to give yourself as much wire as you can. Now, there's two ways to go about this - a) and b).
a) Connect both red wires from the stock connector to the brown/white wire of the Elise connector (the two wires are brown and brown/white) that you've cut off from the Elise contact ring. If yours isn't this colour just have a look at which mates to the red wire inside the Elise wheel as that's the one you want to hook up to power. The other wire (brown one) on this connector will not be used and can be taped back or completely removed. Inside the Elise wheel, cut the black wire as close to the connector as you can. Find yourself a wire ring terminal (
like this) to attach to the end of the wire you've just cut. make sure its big enough to accept the mounting screw used to attach the hub to the Elise wheel. Because that's where you're going to have the grounding point similar to the stock setup. After these connections are made you can plug the Elise connectors together and, when ready, connect the stock horn connectors together and voila!
b) There is a slightly simpler way to do this and I've described the method above only for those who may wish to keep the cutting of connectors off to a minimum. However, you can eliminate a few steps if you like. Cut off the stock connector as per the above and, instead of connecting it to the Elise's contact ring connector you removed, you can remove the connector inside the Elise wheel entirely and then splice the red wires from the stock horn plug and the (now) bare red wire inside the Elise wheel. Connect the black wire inside the Elise wheel with the ring terminal as described above. This is easier and has less connectors involved but if you're squeamish about cutting off the Elise connector from your newly acquired Elise wheel (I'm not) then you can preserve it as per method a) above.
3) AIRBAG: When I first looked into this I contacted a person who had done a conversion from his Esprit stock wheel and airbag (the exact same as ours) and had made up some kits to move to a new airbag wheel. Apparently, he had sold a few to some Elan owners a while ago to and they were successful (if not expensive). He informed me that of the 2 wires for the airbag connections it didn't matter which was connected to which - that is was a simple current passthrough from the trigger mechanism. So, since they've installed several of these upgraded airbag wheels this way successfully and since the Esprit's system is the same as the Elan's I can only assume the same works for us. So............
With the Elise airbag connector you've removed from the Elise's contact ring, strip the wires back a bit. Cut off the stock airbag connector from the stock contact ring in such a way as to ensure you can splice it back in if you want to (leave enough wire but not too much so as the Elise plug isn't long enough when you splice it in). Connect up the wires. Simple.
4. Once the connections are made you'll need to attach the hub to the Elise wheel, thread the cables from the stock contact ring through the apperature in the hub and mount the wheel using the stock washer and nylock nut. I suggest that before you install the airbag you take the car for a quick spin to ensure the alignment of the wheel is right - that its not off center so that when driving straight ahead, the wheel is turned slightly. I just HATE that don't you!
Once the wheel is aligned the way you want it you can connect and mount the airbag (with the car turned off of course). Then, once all the airbag connections under the dash have been hooked up (see below) start the car and observe the SIR warning light. If operating correctly, it should flash around 7-9 times then turn off. If it stays on or doesn't come on at all there is a problem (let's hope not!).
5. There may be other things you might need besides a ring terminal depending on what you got when you bought your Elise wheel and airbag. You'll need 4 cap head screws and washers (preferrably serrated or lock) to mount the hub to the Elise wheel along with some medium thread locker to be safe. These are M6 screws with a length of
(updated) 20mm -25mm. The stock screws are the type that require an allen key to tighten but I plan on using a standard hex head cap screw as they will sit lower - either is fine. Also, two cap head screws similar to the above mentioned stock versions (nice and shiney in the stock version for cosmetic reasons) are required to secure the airbag module to the wheel body. Those will have to be cap screws with allen heads as you likely won't fit a socket wrench into the aperature to get at them. They are also M6 but 15mm appears to be too long - 12mm or 10mm with a washer should be fine. I also recommend some antiseize on the splines of the steering column to facillitate easier removal of the steering wheel in the future as well as some thread locker (medium is fine) on the screws that secure the wheel to the hub and airbag to the wheel.
(updated) You'll also need one ring (if you can find the right size) or spade terminal (spade might be easier to work with) suitable for 16-14 AWG size wire to create your grounding conneciton for the horn. Naturally, 6 washers for the screws are also required. Either 6 serrated washers or 5 lock and 1 flat (used where you decide to attach the grounding wire for the horn) washer will do.Also, its very important that the contact ring is "centered" before you install the wheel. The ring has about three revolutions to each side before locking. If not centered when you install the wheel, you'll find that you can only turn the steering wheel a little bit in one direction before locking the wheel or breaking the contact ring (NOT advisable as i've no idea where one would source one of these now). Be sure you've centered it by rotating it each way to determine how many revolutions it makes before locking each way (mine was 3) then find the position where its 3 turns each way to lock (as it was in my case - yours "could" possibly vary) before installing the wheel.
6. VERY IMPORTANT STUFF: It goes without saying that you MUST safely disarm the airbag system BEFORE doing ANY work on the steering wheel including starting to remove it. This older type of airbag system is not 2 stage and the force of the airbag inflating at close proximity to your head will almost certainly KILL YOU. Can I say that enough??? So, anyone invloved in this little project will not be held responsible for any outcome should you not follow the disarming proceedure properly as per the manuals available through download here on LEC. You are doing this work on your own accord and by ordering a hub you are assuming all risk involved. Once disarmed I also suggest you wait 30 minutes before continuing as the DERM module will hold power for at least 10 minutes after power off/battery disconnect.
Assuming all goes well and you've installed the wheel and airbag and connected up all the airbag systems again you'll want to test your install (with fingers crossed likely). Upon first start I suggest you do not do so sitting in the seat. Reach over from the passenger side and turn the key to the first position (before ignition) to observe the SIR warning light action from a safe position. If all looks good, start the car from the same position and observe again.
I'm not trying to put the fear of God into anyone or suggest this isn;t safe or won't work but I do want people to be as safe as possible and I'll always err on the side of caution.
Assuming all went well take the car for a ride, enjoy a smaller, more sporty steering wheel over the truck sized stock one, better horn button action and the satisfaction that comes from a job well done!