The picco p7r is a nice engine and the OS v-spec is as well but alot of people are going to .28's more for long term durability than power. I rotate a RB Concepts C5 BB .21, with a RB TM928 .28. I like the .21 for big tracks and a .28 for smaller tracks because the .21 has better fuel mileage and less pit stops. If you can spend $280 to $350 I would get the higher line engines for more power, longer piston life better fuel mileage and very easy to tune characteristics. They all scream and they all have loyal owners who think the one they own is the best. From my experience, Novarossi, RB Concepts, and OS have the easiest to tune and longest lasting engines around.