Welcome.
The MY11's are a fun car, I could be biased though
Should be enough modded MY11's around here to give you ideas on what can be done or what should be done
Re: #3 A few people here have a Norm Butler performance exhaust equipped on their cars, (thought that Ultrex has one planned for the MY11 as well).
Re: #4, should have plenty of time to speak to the tuners available locally and then decide who gets your business. Details can be found
here.
Re: #5 If coilovers don't suit, can always look at custom spring/strut combos.