I would have no problem felling comfortable at 100 mph in my Crown Vic, as long as traffic around me was at a relatively similar speed.
I have driven consideably faster than that, but conditions were right for it.
100+ in a Crown Vic? No way... sloppy feel of the steering in one of those babies... unless they've improved that greatly... Just way too easy to oversteer in one of those base fresh off the assembly line. Maybe if it has a sports package that inproved road feedback and feel....
I can and have done well over 100mph, but on a public road in traffic, 80ish is tops for me... of course if I lived out west where the Highways are all flat and straight and drone on forever I might be more comfy at higher speeds... here, where you are going around, over or through a mountain to get anywhere, 80's is fine.