What fuel pressure gauge
 

This may be a stupid question but do I need a certain fuel pressure gauge for the rx8 because it's fuel injected? The ones at the auto parts store say for carbureted vehicles. Does it matter? Also I need some clarification on what exactly I need. Do I need some kind of fitting or adapter separate from the fuel pressure gauge? Or if possible can someone point me to the right one with a link? Thanks.

Search for "RX8 Club fuel pressure test"
Plenty of info there.

You need a gauge that can read from 0-at least 75PSI

And an adapter that goes inline in the fuel line to add the sensor

You can also rent a fuel pressure test kit from Autozone and the like, not sure if they will have a fitting for our type of fuel line but it is a 5/16" quick disconnect fuel line fitting.

Something like this would work to get the stock fuel line to fit a normal hose so most fuel line test kits would work.

Awesome gentleman, this helps alot thank you.