I think you should sell the 545 and pick up a Nag1. They are good to 550hp easy! Just get the MB blue top solenoids and your good to go! The auto stick is badass too! :)
I'm pushing 420 rwhp and nearly 112,000 miles with no issues! Right at 23 mpg at 75mph in a 4550lb brick.
Just my 2 pennies!