intake manifolds

My question is about switch the Mk3 Intake manifold with a Mk4 Intake manifold. I heard this could be done but i have heard two thing... That the Mk4's will bolt right on to the block of a 7mg.... But i also heard that you have to cut the two manifolds into and use the lower half of the mk3 and the upper half of the mk4... and then tig weld them togeather.... if any one knows what i am susposed to do please email me thanks keith

switching intake manifolds

To adapt the MK4 front facing to the 7m you'll need to use the MK4 upper short section and the MK3 lower short section and cut them in half where there most closely matched, the peice you cut and weld is the short peice that bolts on the head, not the plenum. It doesn't have to be TIG welded, MIG will be fine but you do need to find someone experienced to weld cast alum. You will also need a longer throttle cable and a different throttle body. Now that all that's said the only gain to doing this is the shorter IC piping, IC piping not going over the hot engine/turbo, and it makes it alittle cleaner looking. The MK4 front face only flows 8-10 more CFM in 28" h2o than the 7m, the 7m-gte manifold flows plenty for 800hp according to the testing, so don't go expecting HUGE gains when you finally get it on.

What about do this manifold conversion so that you can put twin turbo one a mk3? Would it be worth the time andthe money if i have everything?

The "twin turbo one" and MK4TT manifold are one in the same. I already explained the subject as well as explaining your post.
http://www.automotiveforums.com/vbulletin/showthread.php?t=198809