Especially dual nozzle most would say should be richer. The more meth, the richer it needs to be to be stoichiometric. Every car is different though. I run my single nozzle 10.5 and no leaner than 11.0:1. I've seen dual nozzle guys run into the high 9's on AFR. If your car likes it and it's knock free, than I say leave it. You could still lay down 500rwhp though and run it a tad richer. If it's knock free now, just add fuel though. Leave the alky alone once knock is handled and adjust AFR with the gas.