I was checking out the BKP site, and I noticed they list pickup covers under cosmetic options, but surely covering your pickup in a big sheet of nickel must do something to the tone?

Do pickup covers change your tone or am I just being paranoid? Cause they certainly look much prettier, but I can't imagine them sounding as clear as exposed coils.
Apperently they make the tone a little "warmer". But, I dont have a guitar with pickup covers on it to compare it to my guitar.
My Gear:
American Deluxe HSS Strat
Crate GT212
Vintage '66 Fender Champ Amp
Dunlop Crybaby 535Q
Jekyll & Hyde Ultimate Overdrive
Vintage '74 MXR Script Phase 90
Vintage '77 MXR Flanger
Orange Squeezer (clone)
I took the cover off of my bridge pickup, it made it a bit brighter and added some clarity, but it was nothing mind-blowing. It doesn't matter a whole lot either way.
Who cares? Like the rappers say; ''You gots to have da bling!''
When I heard smoking would kill me, I bought shares in Dunhill and Marlboro - Thomas Geraghty

If we don't change it, nothing will fucking change.
^Yeah, we should all get grills for our pickups. I think I'll have one in ruby that says 'bridge' and one that says 'neck' in emerald.