I got my 408 kit from Brian Adams at
PA Performance. Very nice kit at a very good price, and great customer service.
I got a Scat 9000 series crank and forged H-beam rods, and forged Probe Industries pistons with the kit. Brian also balanced the rotating assembly.
The only difference in installing a stroker kit vs a standard bottom end is that some minor clearancing is required. There are a couple spots where you need to grind the block a little, and you also have to grind a bit off the
oil pump housing.
You can reuse your cam and lifters.
Here's a link to lots of pics of my stroker kit and engine buildup:
http://members.cox.net/petescobra2/engine.htm
Pete