Rear subframe bushing question

[goldhawk]

I got a poly bushing kit from a company called Strong Flex. I dont know if all subframe bushings are like this, but the bottom of it is flat. So, it sits like this:
It just kinda sits on top of the plate, with very little of it making contact

I have seen photos online of Powerflex bushings for 5 series cars, and they have the bottom contoured to fit the lower plate. (I cant find pics of the bottom of 3-series bushings) This kit is quite a bit cheaper then powerflex, so I wonder if they cut corners here.

I was wondering if I should try to shape the bottom of the bushing
Has anyone else came across this?
Looking for some opinions on what would be the best route from here.

Also - I'm worried that if the lower plate is sitting under the bushing and not really up in it, that it will be too low, and will have to be bent down...

The supplier I bought this from has never installed the kit, so he isnt sure about what to do.

[Jean]

Check if there should be a washer there at the very least.

[jlevie]

I don't remember the bottoms of the Powerflex bushings as being cupped. They look just like what you have. The bolt and bottom plate load is carried by inner sleeve and the weight of the car is carried by the upper face. So those should work.

[Holland]

I had AKG mounts before going solid, and they had a thick aluminum spacer on the bottom.

[goldhawk]

Thanks for the input.
There is no washer or spacer for the bottom.
I know the weight is all carried on the top, I just want to do things right...
I think I'm going to install the lower plate onto the rocker, measure how much space there is for the bushing, and if it fits, i wont contour the bottom. If there isnt enough room, then I'll contour it.
I dont believe that bending the bottom plate is a big deal anyways.

[goldhawk]

ah ha - powerflex bushing apparently are contoured on the bottom! ...and the top?

http://forums.bimmerforums.com/forum/showthread.php?t=1640861

I can see how this works well