I noticed the whiteline comp bushings set comes with washers while the energy suspension kit do not come with washers.

Are the washers necessary? should it be a major concern? which brand would you go?

 

I think it is just brand specific, some manufacturers mold bushings a little smaller and require the use of a metal washer to make up the difference in space, some mold the urethane bushing a little bigger so it fits with no washer.

Honestly both brands have a solid reputation, if this was a pure racecar I'd say go energy suspension because their urethane has a higher durometer rating usually (how solid it is), whiteline is a little bit softer (still MUCH more solid than stock rubber) but the tradeoff is less noise and squeaking.

If you want ultimate performance and are willing to sacrifice noise then get the energy suspension, if you want a quiet driving experience that's much better than stock rubber get the whiteline.

Personally if Z1 motorsports made compression rod bushings I'd buy those instead, most of their bushings use a larger diameter metal pin with less overall urethane thickness and a durometer rating similar to whiteline which imo is a better way to make a bushing. Not quite solid, still has vibration and harshness dampening from a urethane insert but just not a LOT of urethane.

 

The energy bushings are not loud installed with energy's choice lubricant. Road feels the exact same.