Fuel pressure

["bill and penny meyer" <pplusb@northlink.com>]

After installing a pressure guage with my new Carter pump, I had the 
following thought:

Why do SU's need such a low pressure?  I half overheard a friend 
mention the needle.  If that needle is the float valve, do I need to 
worry about fuel pressure since I have installed Grose Jets??

I realize the above is rambling and/or confusing, but can somebody 
out there answer my question?

TIA
Bill