1989 190e-2.6 ; 171000 miles ; manual 5 spd

I've bought the chain, tensioner, rails and gaskets from Fastlane.

1. I'm told that labor to get the rails in is 25 + hours. Is this true ?

2. Should I not replace the rails in order to do it right ?

3. Also what happened to the gears? Seemed like in the old days we replaced the gears along with the chain !

Bill