[pothole]

I think the odds of feeling 5hp extra from a car producing circa 250hp are zero. You're talking about an additional 2% power, roughly. No chance you're going to feel that through your butt.

If you genuinely can feel the difference, it must be way more than 5hp. I think anything less than an extra 20hp you'd struggle to reliably detect. That's still a modest 8% boost in power.

I sometimes feel like cool air is helping, but I think it's mostly the placebo effect!