if your car is not a "R" and it has OEM 15" rims then the stock tire size is probably 195x60x15 the 205x60x15 you have is a wider tire and therefore may the reason why you are getting a hard ride and the bottoming out you feel is the tire rubbing the wheel well most likely.

That is why i am using 205x55x15 size, it is a little shorter sidewall and there fore gives more clearance for the tire in the wheel well.

I have never had my tires rub not even over a bad bounce or rough road.

Also all tires are a little different size depending on the Mfg. the same size 205x60 may be a smaller tire from someone else. you can get all the Tech tire data: Circumferance, height, width, etc, from www.tirerack.com i was surprised at how much difference there can be in the same size tire.

Also i am using BF Goodrich Touring TA'a they are 149 mph rated 205x55x15.

Check your manual and see if it says 195x60x15 is recommended, then the 205x60's are the problem.

Dan
1997 850 GLT Turbo