+1 on lowering the engine. I have done it both ways and it is sooooo much easier with the engine dropped a few inches, and dropping the engine a few inches is a 5 minute task.

Also, FYI, I have used hose clamp pliers, and have found needle nose vise grips to be equally effective and a more multipurpose tool. Either work, but it you don't own either, I would consider buying the needle nose vise grips.

One final thought, I bought one type of hose clamp pliers from Sears and they sucked. The heads were held on by little "C-clips" that snagged in tight placed like going after the f hose clamps and then the "C-clip" and the head fall down into the engine bay. Real PITA.

 

I just replaced mine with Forge Motorsports Diverter Valves and did a write up with pics. Took me 45 minutes with the pics and really no special tools.

https://www.6speedonline.com/forums/996-turbo-gt2/350130-forge-diverter-valve-install.html