The only models available were G60 and VR6 2.8 12v SLC I think. Only 18000 were sold in USA and Canada which is nothing.
So I'm glad there were no problems other than a few minor ones which can be expected from a 15 year old car, I like what you've done with the interior. As far as I know the previous owner did the remap before any other performance mods, the cam was done later along with the port and polish. I took the cam out as it was causing problems. But yeah 130bhp sounds about right in fact I thought it had a bit more!
What's the problem with the exhaust?