Sounds about right. you could get a nice shell for 2k, an engine, turbo and some suspension for 6k, if your doing a re spray, that would prob cost over 1k and 1k for tuning sounds right. Since this is a daily car its about right, you would spend so much more for a race car build... One thing though is that suspension could get expensive, Good wheels/tyres, suspension cost a lot and there is also sway bars etc which doesn't leave much for a good engine, turbo and other stuff like fuel pumps, ecu, injectors, exhaust, intake, brakes and all that stuff you might wanna upgrade.
I really dont know, my guess is 10-15k depending on what you really want.