I have to comment on the standard Ford Tremec. The part number for the TKO-600 is the 5008 with a across the board price of $1975.00. The modifications that the transmission needs / requires is to get under the torsion bar support / floor board cross member. A you all know, this tranmission is an internal rail shifted unit. The modifications required to relocate the shifter to penetrate the floor board in the factory position is to machine the tail housing and basically remove the 2nd and 3rd mounting positions for the stock shifter location on the Tremec, machine a new shifter rail to exit the rear of the tail housing, develop a "linkage" to offset the shifter and bracket to retain it. As you can see the modifications are many, not difficult by any means, but usually more than the average person is willing to attempt.
This TKO tranmission is the best upgrade you can do, regardless of who you get the transmission from. Each company uses the same transmission, but the differences start from there.
I run a TKO-600 behind a stroked 340 with 3.55's (70 mph at 2200 rpm).
Tony Edler
Classic Mopar 5 Speed