Some question here,I hope have a little information. Heads: What's a good upgrade that still retains the dual plugs? Intake: I'd like to run an Edelbrock intake and carb but will it fit the stock heads or do they have to be edelbrock heads? Also will a SE air cleaner assem. fit an Edelbrock carb? Exhaust: 2-1 - which has better performance, Thunderheader or SE?