Owned a GTR, sold and got the '11 M3 Comp Pkg.
Have 18k and 14mo on the M3, and looking at GTR's again.
M3 is nice (I have owned many M3's), but once you have had the power of the GTR it's hard to settle for less.
Off topic...but it also chaps my hide when 335's with a $700 chip match or slowly walk from my M3. Diff cars for sure, but upsetting at the same time.