we have a 28ft winnebago aspect and tow an hyundai elantra. it weighs in just under 3000 lbs, The SF will be a bit heavier and most are limited to 5K towing. Now yes the v10 will pull everything but it is not going to be anything you can compare to a diesel. I looked for a diesel rv, found a couple but they were left wanting in the coach areas which is the wifes domain. Pulling the elantra has had at 25-30 mph at time in colorado pulling grades and that is with the 5 star tuner installed. It does rev high for hp but you also need torque to keep it going and the torque range is below the hp range so its kinda hard to match up. On the flats its fairly good. My 28ftr weighs in at just under 13K with partial water tank, full of gas, empty sewage tanks, full lpg. Not much is carried in it as storage space is limited inside and out we average around 8mpg overall towing and not towing. Have seen 10-10.5 in flats in kansas and nebraska but usually that is short lived.
a towed is a good idea but need to match the needs and then be compatible with the rv. Dont see many hundai/kias but be aware you can only 4 down with the standard trans.