first of all, what are you looking for? to be quicker? better handling?
well if you want it to be quicker which most people do go with something like the accufab plenum and Throttle body. totally that comes out to close to 500 and you get definite gains, and you can install it yourself.
suspension - lower and upper contorl arms, or springs, Shocks and struts.
some other engine mods would maybe be a ECU reflash from T&J performance, they did a great job on mine, just got it back and the car runs like new again, sounds better, pulls better, and smoother. I'm sure you will get some other suggestions, i'll come back later for more.
Thanx for the reponses. Okay, basically I'm looking to make this car quicker. I forgot to mention that I already have a catback system installed. Originally I had flowmasters but didn't like the sound. Talked to my wife's cousin who owns five Midas's, who actually recommended ravin's. Put them on for a test and never looked back. Great sound
SInce you already have the cat-back, go where I did - throttle body and plenum - I am loving the Accufab 70mm TB and Accufab plenum, both quality pieces, polished, gorgeous. Then add the C&L MAF and Trueflow tube next. Screams above 3K. Big grins for months.