I've got over 4 gallon on mine, recently replaced the rod and put in ceramic bearings, hands down the best motor I've ever owned. I've owned dang near all of them at some point. I go 10 mins on it all the time.

I run a #5 GRP plug in it, temps right at or under 200, crazy power.

I recently switched over to the MSR 1005 from the 2053 and I think I like it a bit more. Not quit as smooth but lots more power.

I tried the p3 in my first GRP and didn't like it. You had to over tighen it to make it fit without leaking, just spend the other 2 bucks and get the GRP #5 and call it good. I have the same #5 in mine from break in.