Many of us have changed to the Aquajet-ARV, which is rated at around 5 gallons per minute. I changed over a year ago and have had no problems of any kind since. Pressure and flow rate didn't seem to change.
Here is a whole long thread about the problems with Shurflo:
5.7 Shurflo replacement
I didn't make any changes to the wiring, and didn't use the pump relay many mentioned in that thread, although that is probably a good idea.
The mounting hole pattern is different, and the fittings are a little different, but nothing major.