Agreed x2 on both my GP's.
I sold my turbo kit from my black GTP for more than I would have been able to sell the whole car for even if I had left it on, and it only took a few hours to take it off.
Also, I bought my red turbo GTP for less than what the engine/turbo kit is worth and it came with a rust free frame, hood, spoiler, tons of extras, etc.
When you sell - demod
When you buy - buy modded (if that's what you're looking to do anyways)