Um, ok I'm a little confused. There was alot to read there. So basically, a mechanic screwed the engine and now you're out an engine and you want to know what your options are for replacing it, right? The first obvious choice is a rebuild (with forged internals and possibly higher compression, etc, etc). The second choice would be a DOHC engine. If it's of the same year and you have the ECU, wiring harness, etc (that is from the same year as the engine) it's not too hard. The third choice is a DOHC TT engine. This follows the same path as the simple DOHC engine. Both the DOHC swap and DOHC TT swap are becoming bery popular. Before I try to go into long descriptions and explanations in a field I'm not as knowledgeable as I'd like about; I'd suggest going to
www.3si.org , going to the forums and clicking "search" at the top and typing in: dohc swap or dohc tt swap. That should answer alot of your questions. Good luck.
-Jeff