Chris, I think your gears are what's holding you back because we both have the W3Z2 computers that aren't speed limited from the factory. I know mine will hit 140 and I would say + but it's hard for me to do that around here and I really don't like getting up to that speed. I have T rated tires but they handle the speed fine, well, they did once. I just got a speeding ticket last October coming back from Florida so I have a bit of anxiety worrying about troopers and plus hitting that kind of speed. I didn't swap computers for top speed anyway, I done it because they were tuned with more spark, 15 psi more trans fluid pressure and knowing I can pass 130 if I wanted to, plus various other reasons.
It seems like most stock Marks besides the ones with the (93's only) W3Z2 computer normally hit 127 and then they shut down. Maybe some are a bit faster and some slower.