Pinion seal leak at 28,000. Covered by the warranty with no questions asked.
Front rotors warped at 29,000. Caused a slight shutdder below 20 MPH and above 80 MPH. Had it fixed at 43,000.
The LS1 engine is a masterpiece. I could talk and compare all night as my brother owns a 99 TA WS6 and my wife a '96 Mustang GT. In stock form the car performs awesome, especially at top end; it will do every bit of the speedometer's 155. There is also a great aftermarket now.
The lowest points I can think of are the low ride and poor handling in wet conditions. Of those 2 low points I say I have no problem with the low ride nor admitting that the car has too much power in certain weather... just informing you of all the possibilities. Also suspension doesn't handle bumps very well, like potholes or RR tracks. The car is simply a bad-ass, head turning, beautiful machine even at 47,000 miles.
Just bought a used '98 with 19,696 miles on it for $14,988. Nearly loaded, immaculate condition, auto, 5.7 liter, did I say immaculate? Modified exhaust, leather, I also suspect the car's chip was modified too... hauls a-- off the line. Haven't had it long enough to notice any problems. So far it hasn't leaked anything although the brakes do squeak. Hope the rotors are not warped! Also, mileage sucks but what do you expect with a car that exhales 330 hp (manufacturer's 305 hp rating I hear is underrated)!
A true "intimidator" on the street, other cars stay behind me, and don't seem to want to pass me when they're in an adjacent lane. Insurance not bad either, pray no tickets! Tricky to drive in the rain, you can swing the rear end out easily if you apply too much throttle... luckily it doesn't snow here. So far so good, and I absolutely positively love this car!!! Just hope it stays that way... and if you can, buy an extended warranty just in case. Drive safe...