You do not have to remove the dipstick, just remove the bolt holding it to the manifold. 12 mm on both the brace and dipstick. 10 mm on manifold bolts. I have had my intakes vatted and always clean the throttle body. It will never be easier when you hold that cuddly little manifold in your lap. This is a good time to replace those old hoses---again never easier than now. I use genuine Volvo hoses although I use the fcp kit for the trap. Tis all Volvo too.
You will need flexible joints, tools and body joints and patience, but the beer later makes it all better.

Have fun,

dick