Resonator or not with headers?
 

I'm installing speed daddy headers, and here's my question.... It has stock exhaust aside from flowmasters, has anyone gained or lost power from losing the resonator? I'd rather keep it, but if it affects performance I'll take it out. Thanks.

Don't think it'll make a significant difference on or off. You want to leave it, i'd say leave it.

I agree. I don't specifically know what the inside of your specific resonator looks like, but having seen other similar gm resonators, they're typically no more restrictive than a straight through glass pack muffler (ie not particularly restrictive at all).