Sounds a bit like the route I want to take. Having read the Crossflow rebuild and tuning book it seems there is some mileage in making sure the ports aren't constricted too much by making sure gaskets don't impeed the gas flow. Means taking the manifolds off though. I can appreciate what you are/have done is non intrusive.
Yep, it's a good driveable engine as it is - any more significant mods will involve much more time (engine removal) and expense, so happy to leave alone from here!
