I have been using side gapped plugs on every vehicle I have owned for the last 5 years. I wouldn't run a vehicle without side gapping the plugs. I believe any power gain is negligible, but I notice on every vehicle smoother running and easier start up, that's enough for me.

Mike (UK) _____________ 2008 Bonnie Black Special 2010 Speedmaster https://www.triumphtwinpower.com