Do these help? I heard that they increased performance. Does anyone use them?

 

I've used Bosch plugs for about 25 years now in my cars. I don't know how much they've helped performance, but I did notice a long time ago that I have fewer problems with them as opposed to Champions or AC (especially in higher mileage engines).
I'll run whatever's stock in my Mini until it's time to change them, then I plan on switching over.

 

I tried Bosch Platinums in my BMW 2002 years ago - and didn't like 'em;
I had been using NGK's (MINI's OEM plug, btw) in my Classics and other BMC cars and they never let me down, regardless of what type of driving I did (you aren't supposed to drive a Minor like you do a Mini, but i tried ...).

 

I agree with 8ball, NGKs do the job, excellent spark plugs.

Juan