That turbo'ed/nitrous Fox sounds eeeeeevillllllll.
On that empty-arsed, flat, boring-as-hell highway between Florence and Tuscon, I've only once taken my notch up to 120 mph on the speedo, but mine reads WAY off on highway speeds, so it was probably more like 100. Either because of my 4.10's or an imbalanced driveshaft, I get just enough of a vibe above 80mph (on my speedo, which is probably 70mph) to worry me. Plus, I'm only running 15" tires rated up to 112mph, so going above that probably wouldn't be wise.
Someday, I might take my DS into a shop to have it rebalanced and see if that helps. Unless they crap out on me, or the LSD takes a dump, I'm leaving in the 4.10's - I wanna see how they do on a set of DR's sometime later. Even though 4.10's are absolute crap for top-speed fun.
Fastest I've driven any car was just over 120mph in the mostly-stock '94 Crown Vic Interceptor (P71) that I had a few years back. They will supposedly do all of 140mph (P72's are electronically limited to 105), but it takes a lonnnnnnnng time to get there once you've over 100mph. I shut 'er down at 120 because, like my notch, I was running S-rated (112mph) tires and the thing felt a little too floaty for my safety tastes, even with the super-stiff Bilstein HD shocks. (I guess tall-sidewall, lower-rated tires kinda stretched out at high speed, kinda like how you see the slicks of a railcar balloon/squish when they heat 'em in the burnout box.)
I'd sure like to rent a big banked-turn oval track of some kind for a couple of laps in something - any Mustang or a CVPI - and just mash the pedal until it just won't go anymore...
In my 89 notch, when stock down to the 3.08s, Iset the cruise at 125-130 for a good 10-15 minutes until I crested a slight hill on the interstate, and saw two state police officers in the median. I figured there was no need in tapping the brakes until I saw some red and blues. I passed them, they must have seen me, but they didn't move. I didn't brake until a rest stop about 3 miles father. There I changed my pants, and just chilled for a good 10-15 minutes until I could once again hold my hands steady.