I feel you on this one. I did it on my Wrx and had to remove a bunch of stuff. I also unbolted the engine mounts from cross member and raised the engine to get more clearance. At first start up I thought I did it wrong because the engine bay was smoking a lot. Then I realized that it was just remaining residue burning off the exhaust.I also replaced the valve cover gaskets since there was a small leak on the passenger side and slight dampness on the driver side. It was pretty cramped but the passenger's side was not bad but the driver's side was tough. I actually had to do the driver's side twice. The first time I was rushing and the gasket got caught on a cam bolt when installing and I didn't realize I tore the gasket, so when I started the car I was leaking pretty bad. Re did it with a new valve cover gasket the second time by getting all the fuel lines, hoses and harness out of the way .