I've had the car for almost 3 years, and I've got 113,000 miles on it.
For this car, all my mods increase the efficiency. All I'm doing is prep work for when the engine dies (so I'm doing chassis
work, bracing, etc). I'm picking up pieces for the next engine (upper and lower intake
, looking for heads next), but I'm not going to install them until the car's paid off, and I get another car.