Spacers are likely to present a problem. You're already 11mm shy of the +60mm offset that's OEM Spec. If you abide by the +/- 20% rule, then you're already at the acceptable limit for deviating from the OEM spec offset. Spacers will push the wheel out further causing a change in the handling and premature wear on the bearings.
I wouldn't say that simply changing to 17" wheels changes the car's dynamics in any meaningful way provided you choose a tire that, when installed, equals (or closely equals) the diameter of the stock 15" or 16" wheel/tire combo. With a 17" wheel you're going to get a lower profile tire which is both good and bad - probably better cornering due to less sidewall flex but a harsher ride.
A lot of people (myself included) would like to upgrade the look of the car by going to 17" wheels. It seems the lesson here is that you really need to fit a wheel to check for clearance before buying one
Its hard to tell from the pics if a larger diamter rotor (and higher mounted caliper) would solve your problem. It almost looks like it would given where the wheel hits the caliper now. But, it may just move the caliper higher and have it contact the spoke further up. The spokes are very thick (from the face of the wheel in towards the hub) whereas the spokes on the OEM wheel are much thinner. That could be a key point for people looking at new wheels.
Get the spoke thickness measurements from the manufacturer and check it against the OEM wheel. I suspect a forged wheel will have thinner spokes than a cast wheel would. Do you know if yours are cast?
I'd call or e-mail the manufacturer if you can and ask them if they think you can machine off a bit before you do anything else.