Sniper EFI Returnless?

[CP82AERO]

I'll be employing a Sniper EFI on my Windsor-based 427. It should be good for a around 500HP. My question is, since I chose the kit with a "returnless" fuel line, should I be concerned with vapor lock--and therefore install a return line back to the tank? Have any of you experienced with vapor lock with just a supply line set up?

[i.e.427]

I spoke with a builder a couple weeks ago that was talking about the returnless system. It's still my opinion that I would run a return line even if I didn't use it now. Future proofing the car is hard to do but in this case running a return line while building just makes sense.