So i have an 06, base TL with just 90K miles. I bought it brand new. I know several of you have replaced shocks/springs well before 90K miles and I'm wondering, on average, how long is the stock suspension supposed to last?

For me, the ride quality feels pretty much the same since day 1, but i have started to notice a lot more bumps and dips in the road. I also replaced my RSB with a progress bar a few weeks back so I'm not sure if that has anything to do with it.

I was planning on changing to aspec suspension at around 100K, but how long can i go on my stock setup? what are some symptoms of a shot suspension?

 

At 90k miles, your shocks are most likely on it's way out. Not to say they are, but a lot depends on your driving style, road conditions, etc. With bad shocks, you will notice a more "spongy" ride as they won't absorb bumps/dips as solidly. Wheel hop is most likely to occur IF they are completely out and one thing for sure, your ability to stop the car will be increased (more nose dive).

If you've noticed a stiffer ride after the RSB, your assumptions would be correct as far as the sway bar effecting it. That's completely normal.

Personally, if your driving style is conservative, I wouldn't worry about it TOO much but if you're planning to swap out suspension anyway, it'd be a good time to browse around for the best price and go from there.