For a true 'tuned pipe' for a G-62, Macs makes one - http://www.macspro.com/

A friend of mine ran one of the '1097' pipes on his G-62 ( http://www.macspro.com/tunedpipes.asp ). It did indeed give quite a boost in power.

Current price isn't exacyly cheap.... plus you'd still need a header (which they also make for the G-62) - http://www.macspro.com/headers_side.asp

Anyway, I've seen the system work... and it does. Turned his 1/3rd scale Lanier Laser from an iffy 'sport plane' into a real performer.

Just another option to consider -

Cheers,

BJH