The Vspec is definatley a good motor for 2 gallons then get out the Pocketbook.
I run P5's and they last at least 3 times long and are just as fast but dont get as much runtime.
And I dont want to hear that OS has been winning a lot of big races, I know this but those guys dont care if their engine blows up after 2 gallons.
IMO the P5 is a far superior motor for the money.