Here's my .02. Personally working in a classic shop, I've seen hundreds of door panels. PUI is the best (www.pui.cc
) and yes, the assembled versions come with a plastic rail, and yes *sometimes* they can come with a more undesired look to them. But... for every single bad panel I've seen, I've also seen 20 good one's. And PUI, has some of the best service for returning items, from a dealer standpoint.
As for choosing between Un-Assem vs. Pre-Assem.... it comes down to are you willing to do the work and hope you can have it come out right OR willing to take the chance that the assembly is not quite right.
Personally, ask the company your ordering from to personally inspect the panels, and if they decline, have them ship it COD, so if they're undesireable, you simply refuse the shipment, and you're not out "return" shipping costs... If you're still having problems, email me personally, and I'll set you up with a great set of panels.
FYI - If you call PUI, Donna is THE best to talk to, she's been there for a long time. Ashley would be second.
Hope this helps in some small way!