Sorry I'm a newb , but whats the difference between a boost pressure gauge and a
boost gauge ? don't they both measure boost?,
I got the one without the vacuum . Do I need the one with the vacuum?.

 

Two terms for basically the same thing (in my experience, boost pressure/boost gauge doesn't mean much about measure vacuum). Also in my experience, it helps to have one that measures vacuum. If nothing has changed but vacuum at idle or cruise seems drastically lower than normal, that could indicate an issue with skipping a tooth or something. Not a "must have" but I've always had ones that did both.

 

I assume installation is the same?.

 

Yessir. A lot of them use this weird nylon line but I'm a fan of finding a brass nipple (usually 1/8 NPT female thread) and using real vacuum line plumbed into the cabin. The IX MR already has this, not sure if yours would or not.

 

boost gauge, boost pressure gauge.. it's like thinking there's a difference between a road and a street.