I'm in Bangor.

As for the loud pop, that's normal if you have a decat. But if its hesitant, then there may be a problem with your plugs. People say oyu shouldn't gap the Denso plugs, but I say bollocks to that, its only coz some tend to man handle them a bit much and snap the fragile electrode.

Have them gapped to 0.7mm, disconnect the battery for 30 mins, reconnect and start the engine. Let it idle for 5 mins on normal idle speed, then for another 5 mins at 3k revs. Take it out for a spin but do not nail it.

Martin knows his stuff well, but there's stuff that not even he has experienced. Some of the FRS engines are very temprimental...