Bouncy transmission.
 

I can't be alone here .. over bumps and when sliding on anything other than a perfect surface I can feel the tranny bouncing around. Bad news bears. What's the best cost-effective fix for this currently available?

how do you know its the tranny and not the diff?

^^that.

There's a couple of different answers to this: The STI mount, Whiteline and KartBoy inserts, Cusco ring, and Perrin bolt. After looking at the options I'm going with an insert. I like that it should stiffen things without eliminating movement which can cause a lot of stress in a very localized area. The STI wasn't available when I ordered and looks like a better part (to me anyway). But the price difference would have led me to the same decision.

There's a similar list of options for the diff. Have a look around the board and a few vendors sites. You'll get an idea of what your options are. Just make sure you look at things objectively and don't get hung up on branding.

You mean wheel hop??

maybe the LSD making the tires scratch while turning?

The transmission brace uses a very soft rubber and allows a lot of movement. There are a few options stiffening this mount. The whiteline bushing insert is cheap and very effective.

http://ft86speedfactory.com/whitelin...t-kit-307.html