I carry my kart in my Dakota with no frame to kick it over the wheel wells. I simply drop the tailgate and butt the rear wheels of the kart up against the wheel wells. I use one strap around the front and one around the rear to keep it from rolling up the wheel wells if I brake hard. This setup leaves plenty of room between the kart and the cab of the truck for a stand, toolboxes, and other gear. I learned this trick from Rick Schmidt when I picked my kart up from him and have liked it so much I’ve pretty much written off getting a trailer for now.
Here are some quick pictures I took for another guy, so you can get the idea.
What kind of Subie? Any newer Subie should be able to pull a built up Harbour Freight trailer with no problems whatsoever.