My kit started out as an on3 bottom mount, but due to the poor fitment and assorted issues I had with it, I had to modify a lot of the components. Up to this point, I have only retained the original headers and intercooler. I'm also running Comp turbos due to smoking issues I was having with the original turbos, so if you do get a low mount, I'd recommend Comp as you won't have to deal with scavenging.
Ultimately, I would just get a top mount if I were you. It's a bit more proven and looks a whole lot better. Only advantages the low mount has is less heat to deal with and a slightly better location for weight distribution.