Cost of pre-emissions Reman S60?

So i've been looking around to see what the best way to get a pre-emissions truck but with some kind of warranty and still keep the cost under 50-60K.

I'm curious what y'alls thoughts are about buying a pre 2004 freightliner that already has an S60 in it to make all the wiring and such easier and then putting in a brand new Reman S60 with full warranty which I believe is 3 yr 300k.

Would anyone have a rough estimate on what the cost of the engine will be with that warranty?
Is it possible to attach a DT12 Automatic transmission to the S60?
Roughly how much will the labor be to do the engine swap?
Also i'm assuming for the warranty to be valid, it would have to be done at a certified Detroit Diesel mechanic?

 

yes it does, thanks. Any idea what a normal shop would charge to swap an engine out?

 

My concern is that an inframe might not replace all of the parts and since i'm going cheaper on the truck and investing more in the engine, i'd want to make sure that the engine is in the best shape it can be.