yeah Ive drove a couple 96-98 kewbra's, all were over 120k, one had a slight tick on warm up (lifter i guess) but they all would rev like a mother to 7k and had been doing that forever, so yes they are very good engines, i know personally Ive had my gt to red line about 5-6 times everyday for the past year, and it seems to love it, still perfect cross hatching and oil press..
i know that that's a 2v compared to a 4v, but in my experience with both, they both have the potential, if well maintained to last a long time..
the only prob Ive heard of on the cobra's is the irmc's clogging, and having a slight lifter tap on start up..