Earlier this year, I was getting around in a pretty trick GT86 (not really), which my old man and I bought when they first came out in 2012.
Used it for a couple of years, did some minor modifications:
2-way amped Focal splits up front with deadening in doors
Tomei UEL catless header with Kakimoto cat-back (sounded mint)
Blitz dash gauges
TOM's tail lights
Didn't really get to a stage where I felt I would benefit from changing the handling set up, as even though I'd squeeze everything I could out of it, I still felt it had a lot more to give. I ended up getting a good deal on some re003's, which in hindsight, should have been my first mod. The low-resistance Yoki's had nothing on them. The new rubber really helped me get the most out of the LSD as well.