Return vs. Returnless Fuel Feed

[hauen]

So, most manufacturers post '00 use a returnless system whereas almost all before that use a return system. As I understand it, it's easier to meet some of the emission requirements with a returnless system, though in most of our cases, and especially in mine, that isn't an issue at all.
I guess my dilema is, since I'm going to have to plumb everything from near-scratch anyway, is it better to use the post 2000 returnless system (you can build or buy a controller for ~$50, and just one line to run) or just suck it up and run the extra line and such.?
Also, I can't seem to find a straight answer on fuel pumps, will say a Walbro 255lph or similar get fried with variable voltage control? Conversely, will a fuel pump designed for variable voltage fry if it's subjected to constant 12V?
Sorry if it's a naive question, but I've read so much going either way that now I'm all confused. I always thought a pump was a pump was a pump.
One more piece of the puzzle, this is a Mark VIII engine that's only going to make about 300hp, nothing fancy, nothing exotic, pretty much a stock Lincoln engine that was originally a return-style system, that will most likely be fed by a Focus tank and pump (designed as a returnless system)

Thanks for your time.

[TheSilverBuick]

It's easier to lower the fuel pressure on a returnless systems to control injectors at low rpm. Put a return line in unless you get an ECU that varies the pump speed and only use the pump they recommend.

[CDMBill]

For a very good turn-key return-less set-up check out VaporWorx online.

[BKBridges]

The Vaporworx site was an interesting eye opener. Using the big $$ factory engineers output is definitely the way to go. Ive thought about PWM systems but the tank mods/ tank customization tends to be a deal killer. Id like to PWM in-line pumps but both Bosch and Walbro say their pumps wont deal with it...not sure why. Then again, they say they wont pump E85 either, which they do (PEEK impellers and viton seals)...Does MS have a PWM board for fuel pumps?