I would vouch to do a lot of smaller mods than one big one..Personally.
The right little mods in the right place can go a loooong way.
And these would definitely by on my list:
-Perrin steering rack lockdown - $80.00 (Makes handling a dream).
-Transmission and Differential oil change: Motul 300 - $100.00
-Raceseng slammer shifter - $110.00 (this with the oil change makes shifting butter).
-Heard nothing but great things about these two little modifications and the best part is they're freeeee:
http://www.ft86club.com/forums/showthread.php?t=8040
http://www.ft86club.com/forums/showthread.php?t=84622
-Carbon fiber overlay my interior: $120.00 DIY compared to $1200.00+ buying it. (I'm almost done with all my interior pieces and its been so much fun, pieces are turning out so great!)
https://www.youtube.com/watch?v=6rTWaV1imzs"]How to cover parts in carbon fiber (fibre) by skinning or wrapping - YouTube
$410.00 total so far. With a little less than 600 left to play with you can go many routes..
- get a less expensive catback to enhance the exhaust note (wont get much performance)
- put the money towards a decent set of headers (probably have to save it a little but more but this would be my choice).
- Put money towards tires if you still have stock.
- Or money towards coils if you want some low low.
Cheers and happy hunting.