[classicauto]

You can use those "butt weld" fittings - most places normally sell them as "els" (at least up here in Canada) - they'll be alot more heavy duty then tubing. Although tubing will work fine also.

Really depends on you space restriction, the els will be easier to make tight bends (and save alot of cutting vs. tube) but will require more welding etc........its a matter of preference or what the space dictates in most cases.

I don't see a problem with mounting the wastegate at the bottom, except for the fact there isn't much physical space there to put it between the manifold, subframe, and right frame rail. Most tap their runners into the top, then merge them at the gate to the rear of the manifold, making the gate easily accessible from under the car....

But more of a concern then being able to muck with the wastegate afterwards (because in reality, you shouldn't have to) should be where and how the runners are tapped into the primaries. Keep them near the turbo inlet for the best boost control. But alot of locations can work really.......