I am in the middle of replacing the water pump on my 2008 Lexus IS 350. I am trying to remove the water inlet and I have all of the hoses off. However, there is a bolt in a super tight place behind the inlet that I need to remove. Any ideas on a tool I could buy to get this off?

 

That's a very detail video of replacing the WP.
I will be using this to change my WP over the next weekend.
Hope this help.

 

The problem is that I am working on an IS 350. That video is for the 250 and components are in different places. There is a system to the right of the water inlet on my 350 that is blocking me from getting to one of the bolts on the passenger side.