You forgot about intercooler piping, fuel pump, minor oil/coolant lines and fittings, gauges, bov, etc... All these things add up. Then you got towing etc...
$12k will be cutting it quiet close, and the setup will be far from optimum. Myself and Bill are still modifying our setup to be perfect. Which means, return fuel system, modifying/new intercooler/exhaust, retune, etc. If you know how to fabricate and do the work yourself, you'll save alot of money and be much more satified with how it turns out.
But in the end, it's all worth it.