I currently have 57,000 miles on my 2010 IS350. I had H&R springs put on the stock shocks around 32,000 miles, and I remember right after the suspension felt slightly firmer but not harsh. Overall was a great upgrade.

As of recently it feels like my car nose dives during braking. If I need to brake hard I start sliding forward out of the driver's seat.

Going over dips in the road it feels like there's a lot of travel downward, though I've not heard the car bottom out.

Going through intersections that aren't flat, but have a rise to them, I'm typically tossed upward out of the seat. Landing back in the seat has caused me some lower back pain so figured I'd ask if these are symptoms of worn shocks or could it be something else?

I tried the bounce test on the four corners, but the car didn't continue bouncing.

 

Definitely sounds like worn shocks. Especially since you are on lowering springs, this will decrease the life of the stock shocks.

 

Agreed, sounds like worn shocks to me.
If your car jounces a lot with the corner bouncing test then at that point it'd mean the shocks are completely blown.

 

Thanks all. I was considering the F-Sport shocks, but there's a stop sale at the moment. Anyone know when the stop sale will end, or have any recommendations on other shocks that would work well with H&R springs?

 

Koni Yellow shocks would be a great choice and IMO better than the fsport shocks.
It has rebound/dampening adjustments too and could handle the drop.

 

Hi, I have a lexus IS 250 2006 model. When im driving I can hear a noise coming from rear suspension.<br/>It also has a noise coming from the belt that is intense when the car has stopped.

 

Hi, I have a lexus IS 250 2006 model. When im driving I can hear a noise coming from rear suspension.<br/>It also has a noise coming from the belt that is intense when the car has stopped.