Obviously, unless you're just changing things to change them, you should address the things you think need to be improved based on the way you use the car. Someone who autocrosses their 86 will change things differently to someone in the hella flush scene. Do you want to improve performance or looks? If the former, in what way - acceleration, braking, or handling? If the latter, well the sky's the limit and it's all up to what you like.

In my case, I started with Whiteline and Perrin bushings throughout - transmission, differential, crossmember, steering rack, and shifter in several places.

Then I did some small assorted cosmetic items - JMP Coachworks Alcantara speaker grills, leather upper armrests, leather lower armrests, Alcantara instrument hood, Alcantara hand brake boot, and WeatherTech floor liners.

The last six months I've focused on performance modifications - the list is too long to go into here, but it includes wheels, tires, header, catted front pipe, exhaust, EcuTek ProECU, strut tower brace, master cylinder brace, drop-in filter, cas/cam plates, coilovers, brake pads, brake lines, 4.56:1 ring and pinion, and spherical rod ends throughout.

The point I'm making is I drove the car for a while, identified shortcomings, and then purchased modifications in the order that made sense for me.

I agree with Jason. What you should do really depends on your goals and what you're looking to get out of the car.

Me?

I'm not a fan of the stock radio, so the first upgrade I made was to change that out for a Kenwood touchscreen unit. Boom, stereo is better (for the time being).

Next I decided I wanted a little more sound, so I bought an intake. Wasn't expecting any power gains but added tone while laying into the throttle has made the car more fun to drive.

No two people will have the same path, it all depends on what you want to do.

Do wheels and maybe some springs or coil overs, here's the fix to the issue of understanding offset
http://www.ft86club.com/forums/showthread.php?t=7535

What is this cosmetics business?
Oh wait!! I did something cosmetic the other day. I put a slimline front number plate bracket on!!! Literally the only cosmetic change out of the 7 or 8 grand I've spent haha.

As was said at the start, either cosmetics or forced induction. Both costs a lot. One or the other still cost a lot. I still have stock wheels for heavens sakes :D