We have the RAS, and love it. There was site sponsor here selling them at a discount for site members, but I don't know if he is still around. Here's their web site.
I bought my RAS kit from the guy who used to be a sponsor of this site. Not sure why he dropped his sponsorship, but here's his web site. He's a stand-up guy.
if you want you can upgrade just like the other members say...but i always have atv's dirtbikes, and even a snowmobile in my s/t and it was fine!! no problems...the only complaint is a little too much bounce and body roll with the heavier stuff!!