old, just clarifying if someone comes across this doing research:
I had cut 13 CM (not mm) of length off the end of the coil. It took a bit of care to have it sit on the perch when reassembling the shocks & springs, but I just had a buddy help me keep it lined up.
After I had decided to change to different springs, I actually experimented with the back, and I trimmed a few CM off the back springs too. It took a lot more trial and error to get the height 'just so' but the ride was fine and the springs stayed where they are supposed to without weirdness. It did however ride on the factory height bump-stops really quickly so those needed to be trimmed down, which I should have done anyway with the lowering springs. if you consider doing this make sure you cut off from the TOP of the spring, the bottom doesn't have enough coil to grip the seat properly otherwise.
No longer own: '12 V6 Perf, from Sept '11.
Mods: TWM 520g Piston shift knob & Barton shift bracket, AM short shifter. SR 1.5"drop & AM street phb. Tokico D-spec, Whiteline bars F&R, J&M Lca, 25mm wheel spacers, 18x10x4 Bullit style on Sumimoto rubber. Magnaflow Street's. 25' of b-quiet ultimate, 10" JL [email protected] 350w, JL TR's upfront. Bama Tune, B&M 73mm & Shorty headers.
Someday..... Twin Turbo, or SC goal is 450 whp. Has to wait until warranty is up