NO! That's your fuel pressure regulator. NO CUTTING IT OUT!
It's the "pulse" style, so it doesn't have a return fuel line. It "pulses" fuel in to regulate pressure. Kinda blows- we can't use any kind of generic/Honda adjustable FPR on our cars (they use return fuel lines).
If you ran a fuel cell and a return fuel line you could use an AFPR.
But to answer your question, basically, DON'T TOUCH IT!
"Can it go bad?"
Yes, your FPR can go bad. You'd notice an EXTREME lack of performance, if your car would even run. It would make your car run SUPER RICH (or super lean), like pouring a gallon of gas down the TB every minute, or completely blocking all fuel from the engine. Your's is just ugly (you say)- clean it, throw a coat of paint on it, forget it.
"Doesn't the pump regulate?"
Your fuel pump (and any fuel pump on any car) ir designed to put out more fuel than what your car needs, more than likely it will ever need, unless doing some boosting. Your fuel pump pushes fuel at 60-70 PSI (IIRC). Your fuel injectors need the fuel to be at 43 PSI (again IIRC) to work properly. So the FPR is there to regulate the pressure down. The fuel pump does one thing: pump fuel.
"What would happen if it is replaced?"
If what is replaced? The FPR? If you replace the FPR with a new one (same kind!), hopefully nothing would happen. Your car would run the same (assuming your FPR is OK). Replace the fuel pump (same kind or better for more fuel), and... nothing would happen. The fuel pump pumps fuel, the FPR regulates it. As long as the pump pumps and the regulator regulates... nothing's gonna change.
The stock fuel system on the Ford Focus can EASILY handle 200hp- so pretty much, if you're not boosting, you're fine, unless you build some oddball 300hp N/A motor (if you do I want to know how!).
You won't get any performance out of changing the fuel pump. Your stock pump is WAY more than adequate for any non-boost motor! And you'll LOSE performance by changing the FPR- the Focus is right on (actually a little toward the rich side) when it comes to WOT a/f ratios. So... there's no sense in working on your fuel system UNLESS YOU HAVE TO! Your stock fuel system is MORE THEN ENOUGH for any non-boosted motor (it's even enough for most boosted street cars).
If it ain't broke, don't fix it. This is one place on the Focus where no upgrade will help.
one?
