I had my Mondial up a little over 100 (on private property, of course) on a smooth road. The tires have 2000 miles on them and they are 18 mos old. The alignment is fresh. Car feels great up to about 90 and then gets "darty" after that. There is also a noticable vibration in the front. I can't imagine getting it much over 100. Much less the 150MPH supposed top speed. Is this normal or do I have a problem?