Interesting, they gave me a price for a resonator when I talked to them about it, but didn't really recommend it as they said it wouldn't make a drastic improvement.

You did encourage me to look around a bit though so I got looking down another track, which is that the exhaust is currently dual cannons, would it be worth asking to get oval mufflers instead? (ie. would it make a decent difference to overall sound and drone?)

(From what I am gleaning online, if I mentioned that I didn't want it too loud then as a custom set up it really shouldn't have ended up as cannons)