Manual Valve Bodies.. Please teach me.. So confused...

You dont always need to mod the insides, but it's a good idea to at least freshen the trans when adding a MVB. The low band apply is a great peice. But, there are literally thousands running around without them. If you are the type to control your actions, a std Cheeta rev pattern MVB should just screw right in and work. To do it right, I would rebuild the trans with a billet steel forward clutch retainer (what actually explodes in catastrophic failures), a bolt in sprague kit (stock ones can fail resulting in mentionned explosion), billet servo kits for kickdown and low/reverse, a 4.2 kickdown lever, 4 pinion planetaries, and kevlar frictions and bands, and a deep MP pan. With a fresh pump, you wont break that trans should you want to go faster later either.