If you're on a HP it might breach the T&Cs and that's a hire purchase. On a PCP it shouldn't as that's a loan against you, not your car (make sense?) which is why it's called a Personal Contract Purchase.
Not quite right about PCP there. See http://en.m.wikipedi...ntract_purchase
"A personal contract purchase deal (PCP) requires the customer to pay a certain amount for a set contract period of somewhere between 24 to 48 months with the right to drive the vehicle while ownership is retained by the funding company."
However, I feel I've brought up a subject that has drawn us away from the topic.
I agree that you won't notice 10bhp. You thought about wind deflectors or DMB badges?