
but I'll add a bit to answer your original question ('cos i'm more helpful than Mike

)
The bit in your photo looks a bit home made / bodged up to me - it certainly shouldn't be there.
That said, i would imagine that at some point the car may have been grounded and either that section was damaged, or the whole lot was pushed back from the flexi pipe and that bit bent/split.
Nothing to worry about in itself, as it appears that the owner just cut out a section of knackered straight pipe and replaced it with another section......
....as to why it has gone in the same place i can only hypothesize/guess.....
....my best guess, going from the photos only, is that the section was repaired using a second-hand / scrap piece of pipe which was already past its best, but happened to be the right size and available. This is based on the photo showing that the rear clamp appears to be newer than the front clamp, so the repair was done on a budget (I would always fit new ones, 'cos old ones are a pain to tighten up properly if the threads are rusted, or the clamp isn't straight)....
...as to what to do about it - my advice would be to do another 'temporary' repair in the same manner as you currently have (or get a local exhaust centre to do it for you) and before spending out on anything exotic, get used to the car and ensure that evreything else is as right as you expect it to be.
Once you are happy, then consider a new exhaust - there are plenty of options, but the current recognised upgrades are from Peco (Cybox) or Piper.
I personally love the Piper ones, and being 'modular' can be tailored to whatever you want/need, wheras the Cybox are a complete unit of compatible parts with no options.
Bear in mind that Piper have just developed a new downpipe which matches the whole system, so if i were in the market for a new system for an S2 which will be used mainly on the road, with a bit of spirited driving, I'd go for a 2 1/4" system with the new downpipe and a sportscat.
You would probably be quite happy with just the main system and sportscat, and leave the pre-cat in situ - but i would consider removing this obstruction as they have been known to break up internally and cause later issues - although a good idea in theory, they have a very limited effect on emmisions, and the car should be good to pass the UK MOT without it, and some seem okay without any cats fitted.