Actual specs for curb weight are:
I-4 M/T: 3042 I-4 A/T: 3091
V-6 M/T: 3243 V-6 A/T: 3311

That's about 200lbs more weight in the 6... and I'm not sure how hard or easy it is to get a 6 without a sunroof, but I recall reading that almost all SVT's have sunroofs.

2003 Mustang GT 5-Speed, FMS 4.10 gears, Dr. Gas O/R X-pipe, Flowmaster cat-back, BBK CAI, C&L intake plenum, Accufab 75mm TB, Steeda Timing Adjuster - 13.70@102.23 (SOLD) 2000 Cougar V6 ATX with many mods - 15.93@86.97