I just saw the new top gear episode comparing the Jaguar XKR-S to the GTR. The GTR obliterated the 540HP jag on all counts. It also looked great in blue.
While it would be great with a manual offering, I regard the GTR as a more extreme version of the M3, perhaps with a little bit more towards the track and less so towards the luxury.
I cannot wait for the opportunity to test drive one.
On a side note, I know a guy who has a GT-R and HAD a track prepped E92. He wasn't the most experienced driver and after a few hot sessions in the GT-R, he jumped into the M3 and put it into the wall and totalled. It was on the entry to a relatively slow speed corner. I think he didn't adjust his driving style to rear wheel drive and take into account braking distances between the two cars.