2003 GT VVTL-i Problems

mattcrystal1

I had the engine replaced in my GT and I heard there are 2 different VVTL-i engines. I bought a used one and had it replaced. Before it was replaced it would hit 6000 rpm and take off like a bullet. With this other VVTL-i engine it falls on its face at 7200 rpm. What are the differences between the engines and what would cause this? Any kind of help would be greatly appreciated.

Thanks for your time,
Matt