Hey I have a 255 & im none of the above lol....
No offense, but a number of us thin you are washing out your cylinders with too much fuel. You have only ever defined "no problems" as "I don't see any yet". It's known that the regulator's stock spring is too weak for a 255.
Could go with an Aeromotive Stealth. I want to swap out my 255 for one.
This guy... the OP... do.... not.... need....
Unless he's going for BIIIIG power numbers, he doesn't need the 255. Period. So he also saves money and time because he also doesn't need an aftermarket FPR.
No offense to Jason (sideways) or to Colin (Draconis), but neither of you represent the average modestly tuned setup. Jason, you just throw in a buttload of fuel and don't really fine tune, so you're never sure what's really going inside the engine... and over time that could have bad results. Colin, your beast needs a lot of things that a modestly tuned (boosted) four cylinder doesn't.
The Walbro pumps were a favorite in the DSM world, long before most people here were even out of high school. We used to laugh at the noobs who would wanna go "big" and buy the 255, and then when they had their cat-cons clog, saw detonation, and were unable to control their fuel flow reliably (stabilly) because they ran too big a pump on a stock reg... when there were guys running the 190lph model, pushing 17psi on pump gas, putting own ~275hp.... while the people with 255's carelessly thrown in were busy sorting out their unpredictable fuel (or buying more parts like the FPR) the 190 guys were actually moving on to well-controlled tunes.
Yeah, we laughed. Sometimes we even tried to educate them. Some of them listened, a lot of them didn't.
Just depends on what you want out of your engine I suppose, but really unless he's gonna be going for some respectable power limits, the 255 is overkill and will need an adjustable FPR (which will be another variable to tune) if he doesn't want to wear out his cylinder walls and rings in the not too distant future.
190 means it bolts right in, you change NOTHING else, so you don't have to spend extra $$$, and you don't have to tune anything (like an adjustable FPR).