There is more that can go wrong or be installed incorrectly on the TT systems. We wont e-mail tune them for that reason. You can send out a perfect tune, but if something was done incorrectly upon installation you can have major problems.
Eric that was a very nice offer.
OP, did you confirm the actual damage or was the cracked piston an assumption? I don't mean to be a downer but it is rare that there is no residual damage to the head or cylinder wall. A used set of pistons will not likely be a cure here.
Like others have said, keep the car and be patient. Do things right and the reward will be very satisfying. You said it yourself; fast, cheap, reliable..pick 2..that said I would recommend you also get a return style fuel system instead of that boost-a-pump.
I haven't checked and don't plan to. While JPC's offer is MORE than generous, I'm not going to put used or even brand new oem pistons in. I'm going to buy another block and build it with forged lower compression internals. I'm probably going to have JPC do the build to be honest.