Don't be put off, just be aware that you need to spend money on more than just the engine.

People who bought the HPI MT (and MT2) were a bit stuck like this for a while, the HPI MT's stock drivetrain is not really up to much, but then they released the MT18SS, which is a beast with a powerful HPI .18 engine. As a result, they had to uprate the drivetrain to cope with the new powerplant, and now we have hardened steel drivetrain components available which can also be used by those with older models who want the extra power. What is the buggy, just out of interest?