here's my suggestions, do a Silvia front end conversion, stick with the stock bumpers, do the kouki tail lights, have the factory wing removed and the holes welded, it'll prolong the life of the hatch, and repaint the car a nice normal glossy dark blue, anything overly flashy will catch 'flak' about beind rice. For the Carbon Fiber hood, I suggest getting as close to OEM as possible and if you do the Silvia conversion, remember to use a JDM Carbon Fiber hood.Wheels, since you're saving by not going overboard on the body, go overboard and get your son some Volk TE37s in 17s with the aforementioned tire size and some high quality wheel locks, he will thank you later. Brakes, upgraded brembo rotors all the way around with some nice new pads will make a WORLD of a difference and still be reasonable for a younger driverSuspension, coil overs would be AWSOME and they're within your original budget but the KYB AGX Shocks and the Eibach Pro Kit set up will leave you with money left over for strut tower braces and upgraded bushings if you choose to go that route, which would be REALLY cool.
you mentioned seats, I know the other guys said to avoid it because the stock seats are great, and its true, the stock seats are awsome, but you're trying to make your kids day here, right? I suggest a Sparco Torino 2 in dark blue for both front seats and reupholster the rear seats and door inserts to match, the interior would be about as perfect as it could get, and with the stereo set up you're talking about adding your son would be in heaven.
For intake, I have the Injen Cold air, if you go that route advise your son to avoid high water at all costs, it cost the last owner of my car an engine, and in the long run, his car. But if he's responsible, which it sounds like if you're doing all this for him, it would be well worth it.
For exhaust, the Apexi N1 Duals have NOTHING but good reviews from everyone here so I would suggest going with that, and a Hotshot header and high flow cat would take that to the next level, and really round out the package.
I've been helping car clubs and friends build award winning show cars and the most beautiful street cars for years.....people have come to refer to their moments of inspiration as 'a mike moment' within a few local crews, you can contact me on AIM at Flyinsol0 MSN at
[email protected] or email me at the same, I love helping people make their cars look the best possible.