Originally Posted by Poguemahone
Don't do it. You have several advantages with friction shifting, not the least of which is almost all drivetrain parts will work with it, where friction systems require a dedicated system-- not only will you need new shifters, but new mechs, new chain, new cassette/freewheel. You can trim shifting with friction. Many friction systems develop problems where they need to re-adjusted to shift properly; in practice, not hard, but a PITA when a problem develops in the midst of a ride. If you're used to friction, keep it.
The shop is likely going to charge you beaucoup l'argent. You want a shifting up grade, get some simplex retrofriction shifters, about forty bucks on ebay.
Everyplace where a dire consequence was mentioned in the above post - replace the work indexed for friction.
Granted, the only indexed systems I've used are cheap ones on cheap MTB's, but I despise them. Friction all the way for me.