If you're picky about your truck, I would say not to waste your time with slip-ones. You'll never be truly happy with them. There's a reason you can buy them by the armload on places like Craigslist...nobody else really likes them, either. Save your $$ up and buy some replacement tow mirrors. They're pretty reasonable on Amazon and other online retailers. I consider myself a little particular about my rig as well and am glad I went with the replacements. My buddy went the slip-on route and changed them out after one trip after seeing mine.
Ode to the Forum Moderators
May the Mods grant me the serenity to accept the opinions of those I cannot change,
the courage to offer valid input to those who are open to another way of thinking,
and the wisdom to shut myself down whenever I get too in love with my own misconceived brilliance.