I have an 88 TII, and I just finished pulling the turbo and manifold off to be replaced by an S5 turbo and manifold, and I have a few questions about the differences:

1. The actuatator to the front and underneath the S4 turbo (the big round cylinder thing) is for the twin-scroll, right? So do I just plug the vacuum line that was feeding it since the S5 doesn't have twin-scroll?

2. There's an extra small hole in my block and gasket that's behind and slightly below the rearmost exhaust port that aren't in the S5 turbo manifold, it's just blocked off. Will this be OK just bolting it up?

3. On the cold side of both turbos, there's a line that goes from the intercooler side of the turbo down to a solenoid or something. The S5 line has a T in it that the S4 doesn't, where does this go? Should it just be plugged or what?

4. Finally, should I put the heatsheilds back in? They were a big freaking PITA to take off, so how important are they?

I wish I had my digital camera to post pics of this stuff, but I loaned it to the in-laws

Anything else I should know about this swap? Thanks in advance!

 

Copy of my answer on TeamFC3S.

As long as you're talking about the twin-scroll actuator and not the wastegate actuator, then yes.
Dunno about that hole sorry.
You're getting confused with something else. The S5's wastegate actuator line has a tee in it that goes to its electronic boost control solenoid. The S4 does not. The line from the IC you mentioned is something else not related. Remove the wategate line (both the steel and rubber parts) and either put the S4 one on or just run a new rubber line.
Yes. They protect other things in the engine bay from heat so they'll last longer.