So i was going to do cbr mirror mod

[Vsekvsek]

But the screws holding old base plate will avsolutely not move. Even tried my ryobi 18v drill and they still wont budge. Sprayed teflon and wd40 in there. Nothing.I dont want to strip them. Advice?

[simi_ed]

Impact driver.  If you don't have one yet, go get one.  <$10 at Harbor Freight.  Once you use it, you'll be glad you spent the few dollars. 

[Country Joe]

Absolutely essential for working on motorcycles.
Joe

[FJmonkey]

Yep, +1 on that tool

[airheadPete]

Yup, +2.

Try a little dab of valve grinding compound on the tip if you've buggered up the heads at all. It might be a little awkward since you don't have three hands, the fairing support is gonna try to flex when you hit it. Grab a buddy to back it with a piece of wood or something.
(And check it's set to loosen, not tighten. I don't get why in the f*#! you'd want to tighten something with an impact driver, but hey, it's a free country! Sorta...)

[Pat Conlon]

Geeeez guys, that gives me the hebee geebies....

I would be leery about using a impact driver on that mirror base, part of the fairing subframe...

I think a kinder, gentler way would be drilling and easy out..

Our fairing plastics are getting more and more brittle every passing year.

[simi_ed]

Pat, there's really no impact to the plastics because of the subframe.  Just a decent hit with a 2 Lb drilling hammer will do the trick.  That's how I got mine loose the 1st time with no damage.  Now, if you tried to do a Paul Bunyon with a 10 Lb maul that would probably do in the surrounding plastics.