First off, welcome to the forum...It's nice to see more people coming in.
IMO I think these Celicas look good with absolutly no body mods. The only thing I would suggest is a nice paint job and some nice wheels (the wheels make the car :D ) with the right offset.
Anyways, I'd start off with I/H/E. Most members replace their stock sir box with an open element air filter. All you need is a conical filter and an AFM adapter. ou can get both these from
www.toysport.com or
www.cyberauto.com For around $60.00. For headers, There is not a big selection, from what I know there are Thorley and Pacesetter...I have heard nothing but good things about DT headers, but the exact opposite for Pacesetter. Toysport is in the process of making headers for the 22-RE using the DT design (hopefull be done in a few weeks) For exhaust, I plan on getting 2.25 in exhaust piping made from my local muffler shop, a high flow cat, and maybe a N1 style muffler.
From there, I would do suspension. Bushings(if worn), new struts, shocks, and springs. Companies like Tokico and Koni make struts for our cars. You can get some F coilovers (sleeve type) from GC. Springs are up to you.
Sorry this is getting so long, it would be a &$#*% if I wasn't posting in the right thread
Just have fun :D