While my boat is not a Sirius it is very similar size and weight. I tow with a Jeep Cherokee Trailhawk. Lake is just over an hour away. Drive include backroads and freeways. Tow rating is 4500 lbs. Trailer w/boat weighs 3000 lbs. No trailer brakes.
The Cherokee makes a very good tow vehicle. The distance from the hitch to the rear axle is very short. This makes it very stable. The wheelbase is long, compared to the total vehicle length, which also helps. The Trailhawk has a few advantages. It has off road tires, which are stiffer than car tires. It has Koni FSD shocks, which work on a different principle than normal shocks, making them much better than any other shock made. Damping rate is inversely proportional to the motion rate. This makes it soft on bumps, and stiff on body roll. It also is a true 4WD with low range and electric rear locker. This helps on slippery boat ramps. You can also put the whole vehicle into 22 inches of water, so if you are on a shallow ramp, you can back the car in deep. The tow package also includes anti-sway brake control. It will sense trailer away, and brake side to side to correct it. Power wise, with a 9 speed transmission, you never know what gear you are in, but it always seems to have enough power to get the job down. I weighed it, and it weighs 4600 lbs. If you order the vehicle, make sure to get the $1500 option with the adaptive cruise and steering assist. It may seem like an unnecessary gimmick, but once you have it, it just makes life so much easier. The other funny option is ventilated seats, which drys off your swim trunks if you slip on the boat ramp.
It depends whether your 21/22 towing load is 1,300 lbs. or 3,800 lbs, whether you tow in flat land or the mountains, whether you tow in 35 MPH zones or 75 MPH highways, whether you launch and retrieve the boat from the trailer or a lift, whether you tow for 1 mile or 1,500 miles and also the number of crew members you intend to carry. Depending on the answers the vehicle can be a Honda CRV or a Ford F250.
I tow my 21 with a six cylinder FWD Ford Escape. For street and highway towing it is fine (I defeat the overdrive the whole time) but pulling out of the water up a steep gravelly concrete slope is a real sweat. I've had to ask a 4WD mate to take over on one occasion. I think I'll go back to 4WD with the next vehicle. Besides, with global warming we are getting quite a bit more snow now (go figure) in southern Québec and the 4WD will be reassuring. Not to be confusing: I don't sail in winter etc...