hmmmm. I've just been through this process with my TT.
I put it up for a high price,with the mods still on (nothing crazy: Remap, rims, lowered, few carbon bits, induction etc) and got the full price. In fact i got a grand more that i paid for it 2.5 years ago!!!
There are definitely people out there who want one already sorted.... So i would say try it with for a while first...
As long as it's mint, low miles and looks improved, as opposed to modified i think you can shift it.