I spent a lot of time and money on mine last year trying to get it to work reliably, correctly, and better. If you are going to go down the electric pump path, then the Vulcan kit you have is a good and easy way to go. If I had it do do all over again and didn't have a ton of time and money already invested then I would choose the Rasp mechanical pump route. It is not cheap, but adding up all the cost for my pump relocate and replacement pumps so far I think I've spent about what the Rasp is going for.
Your stock return line should be fine. Probably no need to modify the tank pickup.
-Deon