And speaking of Lexus over-engineering, anyone know what these rubber blocks (stoppers?) are for? They were attached to the OEM bushing brackets facing towards the rear mufflers.

 

iirc they are mass dampers.

 

According to the interweb dictionary: "A tuned mass damper, also known as a harmonic absorber, is a device mounted in structures to reduce the amplitude of mechanical vibrations."

Sounds scientific, but in layman's terms - what are they for and is it ok to leave them off?

 

yeah they are dampers to minimize vibrations. leaving them off will just add vibrations that are probably so minute you won't even notice. i do love that lexus put them there just to extract that next level of comfort!

 

Yup, the 13/16" size was right on the money! This time I ordered from a company called Prothane (item #19-1107) on Ebay. You can get the bushings in red or black plus they offer two sizes of brackets. Get the smaller size and they are nearly identical to the OEM brackets (minus the wierd damper blocks). Pictured here are the Prothane brackets next to the Energy's. No grinding or mod'ing required; just a little grease and black paint and they went right in. Win!

 

Prothane# 19-1107.

Hey they are made in USA and have good feedback. I'm going to try a set.