Hmmm your setup is very fast, while still using less components for tuning than the others (eg. no LSD, no VCD, no AYC). To me personally I think that the car car should have been under the 420hp rule, and not even a slightest bit over like the 421hp of your car. Even with wearing the engine down you still get the added benefit from the parts used (eg. sports muffler has less overall torque than semi-racing muffler that's been worn down.)
I drove some laps in the car and the best I could get without going off the course was a 6'54 laptime. That was done after I got a 2 second gain from the last lap. For me I couldn't see how you could of got 6'49, because I went flatout on my flying lap. Extra gain tops for me could've been 2 seconds but that's it.
I dunno, I guess I'm always cynical towards people who can do something better than me, and that I can't see what they're doing...Jealousy really. I simply can't comprehend how you could get a extra 5 sec gain on my 6'54 laptime