Which air gap manifold?

Thanks guys, you have me still in two minds. Truth is, the car will never be making less power. so i'm tempted to go for the rpm higher performance option.
The car is for fun use only so i can afford to compromise. Currently i have the XE262 cam and the 'stock' ish Performer intake.

Interested to know what extra power i will feel by moving to XE268 cam and air gap performer intake,and if it will hit drivability very much, if at all.