I just did a 255lph pump in my 03 a few weeks ago. I had to cut the shroud down because the pump was taller than my OEM pump and it would not fit. In any case, the piece has a clip on both sides that secures it. So as long as it is snug and secure you should not have any problems. As far as the pump seal...I didn't check mine when I did the install (I should have tho). Looking at yours, I can see how it might leak and cause some issues with the pressure. You're better safe than sorry when it comes to fuel, so I'd recommend trying to find one off a parts car or Ebay or Craigslist. They're cheap...