primavera

Those are rear upper strut (rubber) bearings, bushings, mounts, however you want to name them. They're sold as a kit, so you need two (2) of them.

ELexis

Thank your following up and posting the additional information / photos. I appreciate you taking the time and doing so.
Would you know the part number associated with kit needed?
Wanting to install items associated with the ST - Sport Tuned suspension package i 2006 - 2010 IS 350);

48510-80257 FRONT RH SHOCK ABSORBER
48520-59285 FRONT LH SHOCK ABSORBER
48131-53171 FRONT LH & RH COIL SPRINGS
48680-53031 FRONT upper strut mount assembly. Left & Right (includes the rubber boot and spring insulator)
48530-80289 REAR LH & RH SHOCK ABSORBERS
48231-53151 REAR COIL LH & RH SPRINGS
48750-30150 REAR upper strut mounts (Is this the kit)?
48341-30110 - Rear Coil Spring Damper / Bumper
48257-30070 - RearUpperCoil Spring Insulator (L & R) ??

primavera

Shocks from the dealer should come with the upper bushings (parts 17 and 18). If you get aftermarket shocks you’ll need to buy those separately. RockAuto sells them for like $5.00 dollars.









48750-30150 REAR upper strut mounts (Is this the kit)?
It’s the part # 14 on the diagram... unless it's badly corroded or broken you don’t need to buy it. Even then I would buy it used from auto wreckers.

Optionally you could buy upper and lower spring insulators #11 and 12, but honestly they rarely ever go bad. AWD and RWD use the same parts.
RockAuto doesn't seem to have them.






Sorry if this is a bit of a head scratcher. Lexus springs and shocks are quite confusing to everyone.
Hope it helps.

ELexis

Thanks primavera1 for following with the additional information. Yes, is somewhat confusing. Vehicle has less than 90,00 miles/ RWD, so perhaps won't replace the following part (ust install the Sport tuned shocks / springs, which I was told come bare. I assume Sport Tuned part numbers are different from vehicle not equipped with the sport tuned suspension);
Have the following additional pat numbers;
48158-30020 Front lower spring isolator
48680-53030 Front shock support assembly
48750-30150 Rear shock support assembly
90948-01090 Rear strut mount cushion
48341-30110 Rear Spring bumper