What are you looking for from the car? The WRX STi should be a very good performer (and probably make a lot of people who bought the normal WRX when it first came out feel pretty stupid) and I think the new mustangs are looking pretty good. Problem is, there both around $30k. I don't know how good the pay is at your new job, but if you take on that additional payment, your probably not going to have much money to do modifications. Basically, do you want a car that's fast from the factory or one you can work on during the weekends and make fast yourself.

As for Civic's not being good for racing, that's not really true. There are normal problems involved in racing a fwd car, weight transfers to the rear during a launch and off the drive wheels and with most of the weight up front, understeer is also an issue. That said, they can stil be extremely competative with any other car out there. You may not have an easy time with a tubbed out muscle car that does wheel stands and runs 9 seconds but you'll be a pretty good match for any street car (depending on your mods) and a B18C1 swaped civic is a fun car to drive. Seeya.