So right now you've got a 3 speed/small tranny hump? A T5 will bolt up to your bellhousing. You just gotta drill the metric mount holes out to 1/2". If you've got the small hump, I'd think you'll have to modify the floor a little. As for a x-member, you don't really need one. I've had my T5 installed for a year now without one and it was my daily driver until 2 weeks ago. I've been fabricating my own mount that attaches to E brake x-member and bell x-member and then attaches to tail shaft. Using shock bushings, general idea is just added support/sturdiness. The mount/brace has been 80% done and not installed for 6 months now so...
The tranny probably only weighs 80 something lbs. with fluid and most of the weight is forward where you've got 4 big 1/2" bolts keeping it in place.
I took pics and wrote text for my swap which you can see here under "Files": Kustoms-and-Sleds . Since it's a Yayhoo! group, you've gotta join to be able to view the files. I tried to be as thorough as possible with my pics and write-up.
-David


Tradin' up dimes for nickels...
'`'`'`'`'`'`
My \'65 Chevy C-20