I've done this mate, you need a decent mani with external wastegate port, you will also need either a downpipe making with a dump pipe from the wastegate in it or if not a screamer pipe which avoids things in the engine bay. You will then need a wastegate with spring, I have a Tial one but some people recommend the cheaper ones. As for the internal wastegate, either get the penny welded up, get the arm the actuator attaches to tacked(if you ever want to undo this you can just hammer off the tack which is how i've done it), you can also use a bracket or even just keep the actuator attached with no vac lines on but this is somewhat of a bodge. You won't really gain any power but I feel it allows you to use the power of the car as i found with all my mods and a ported wastegate i would creep to fuel cut in seconds even at 0.3 bar, with the external you can set it to 0.8 bar and spool up rapidly to that and it will hold there without overboosting or dropping off significantly.