I thought it may be helpful to share my recent experience in replacing the rear struts on my wife's 2009 Lexus RX350 FWD with about 132,000 miles. I had to replace the struts because the right rear was leaking and the protective boots shredded. I did a lot of research and found a lot of good information on Club Lexus and Youtube which I really appreciated. Having completed the job, some things I came across make more sense now, especially related to parts selection.

I ended up buying the Monroe OESpectrum Struts and the Monroe Strut-mate mounts. I considered the KYB's, but there seemed to be a lot of concerns expressed about how much stiffer they were than the stock struts. (I would have preferred to by Lexus struts, but they are significantly more expensive!) I didn't encounter any issues when installing the struts and everything lined up perfectly.

I'm not as happy with the Monroe Strut-mate mounts, and I wouldn't recommend buying them. There are a couple of reasons why I bought these. 1. The stock mount and strut bellow are one piece and I wasn't really sure how well having a separate mount and bellow would protect the strut rod or how one would attach the bellow to the mount if that was necessary. 2. I read a couple of threads about making sure your mounts and struts were compatible. The problem I encountered when assembling the struts is that the keyed area of the mount that fits over the strut rod to secure the mount is garbage. It either has too much play or the metal is weak or not thick enough and therefore allows the mount to spin out when trying to torque it to spec. The stock mounts look thicker in this area. (Tip: To make sure that i had the mount properly mounted onto the strut rod, without the spring on the strut, I placed the mount correctly onto the strut and used a permanent marker to make alignment marks.) Based on my experience, if I were to do this again, I would buy Lexus rear strut mounts and there shouldn't be any compatibility issues.

WIfe says the car drives so much smoother now and only time will tell if these Monroe struts will in the long term, deliver a quality ride.

Now I need to figure out how to determine if the front struts need to be replaced or not. I've pretty much decided to use all Lexus parts if/when I need to replace the fronts cause I've read enough concerns about using aftermarket parts that I'm concerned that ride quality would be impacted.

 

Funny! I had Rock Auto up on the computer ready to order new struts last night and decided to do more research and this came up.

I'm in the same boat at 151k miles- thank you for the heads up.!

Mayble I'll give these Monroe Quick Struts with all new everything a try from Rock Auto for the rears @ $125ea and avoid the hassle.
PN: 72212 Left FWD
PN: 72211 Right FWD
For the front struts I'm going to lean on the CL members here and see what ya'll are using and happy with before I buy anything!

 

The only reason I didn't buy the Quick Struts for the rear is that it was about $60 more per side and I own a pair of spring compressors. And $125 is a great price and will make the job super easy.

Good luck!

 

I know this thread is a little old but I have a few comments.
First, it’s my understanding that the KYB struts ARE OEM. I’ve used them on my RX and the ride seems perfect.
Second, I’ve heard from multiple sources to avoid Monroe struts because they are garbage. I’ve used Monroe on my Honda and they did not install easily, the ride was dissatisfying and they did not hold up over time.

 

I have a question on the stock struts 2009 RX350 they are oil filled, i have the 18 inch wheels tire pressure 30psi when i go over bumps the rears make a thump noise as they de compress, getting back to the fronts hitting bumps feels like i have off road stiff suspension.. will new shocks using stock springs make it a softer ride. Pushing down on all four shocks feel very firm, maybe i was expecting a nice soft caddy suspension. I will do the rears first, can i use the stock rear top mounts with the KYB or Munroe....so KYB are OEM.. good and bad reviews on both lol ... so it looks like i can not use stock top mounts with the Munroe shocks and boots? confused so do i have to get the complete assy.... 330 let me know how it rides with the rock auto complete shocks

 

KYB manufactured the OEM struts for Lexus to Lexus specifications and to be branded as Lexus struts. Any KYB-branded struts on the market are NOT the same as the struts manufactured for Lexus.