I understand how you feel mate. I have been tempted to sell mine so many times due to problems created by others. It turns out, the first machinist failed in every aspect of the job he was paid to do. Fortunately, I have found one of the best around and Im almost there. Also had issues with the gearbox being rebuild three times and it still leaks!
Still, Im pushing through with the end now insight. Hopefully you can do the same.
If I had that engine expire, I would throw it out, buy a camry half cut with a 3.5ltr VVT manual, and fit that instead. Word is, its an excellent package, sounds brilliant with the right exhaust, very quick and very reliable.
You could sell the box and engine bits to buy the half cut. If this 3SGTE of mine fails one more time, expect to see this package in mine next time round.
Best of luck