[SactoJim]

Here's mine (24") mounted on the frame rail on passenger side. I used "push-on" style fittings to plumb it. Hasn't seen alot of road time yet, so I don't know how well it works.

Another nice thing about having inlet/outlet on same side is it's easier to plumb.

Also.....I don't think one is better than the other in regards to cooling (dbl pass vs. single). When I looked inside mine it looked like one big chamber and even if there was a divider down the middle to get "dbl pass" you're still only using half the cooler on each pass.......just can't see it making much of a difference. It's all about surface area of the cooling fins.

I would just get the longest one that will fit your application.