My mount has been broken ever since I bought the car, but it's been driving smoothly because of the amazing engineering done on those mounts.. it can break and still support the transmission. So I took that one out and replaced it with a polyeurathane one but it didn't fit. I drilled into the cross member or whatever that metal bar crossing the mount is called and finally got it to fit. Now my transmission is a little too low and when i shift into second it's fine but when i downshift into 2nd, like applying more force to it, it pops right out. I believe this is due to the fact that the transmission is lying too low and it doesnt go down into second all the way. My car also started to make really loud vibrations and noises when I drove it after installing the new mount, too. I have no idea how to describe it but when it is idling it seems to rumble more and when I try to ease on the clutch in first to get it going it feels like its about to stall. Sorry for the run ons and bad grammar but hey, im only 17 years old so what do u expect with all these new facebooks and twitters and crap like that..
I probably forgot some things so I'll just post them when I realize it.

 

The urethane mount usually comes with a separate sandwich plate. Did you install that as well? You feel more vibrations because the stiffer urethane transfers more through it. It's a trade off for a more durable mount. But if you don't like the vibes, you'll have to go back to a conventional rubber mount.

 

I found out that although Summit Racing said this is the right mount for my car, I purchased the wrong one and I'm going to have to purchase another.. My whole tranny's moved back so far I can barely shift into second