suspension - get some springs to drop about 1.5" should be fine, will help slightly with handling. cost should be around $200 -250.
Handling wise i'd recommend a rear swaybar will be best bang for buck on this car.

Exhaust get a cat back 2" will be fine. Mandrel or press won't matter too much.
A good quality muffler will help, Magnaflow make some nice ones. again about $250+ depending on your muffler.