Wich do you recomend and why for a 20' car hauler.

 

always go gooseneck if you can.Over a Tag its night and day.Over a 5th wheel well about the same but Goosenck cost less and its only a 2 5/16ths ball in the bed.The 5th wheel takes up so much space and is a pain to remove and install when not in use or to install.You can leave it in all the time if you dont need the bed of your truck for anything.The gooseneck i can pull a rod in the rear left wheelwell and pull out the ball and flip it over and ive got the whole bed in 2 mins.

Gooseneck installed $600.00
5th wheel installed $ 1200.00

 

Gooseneck should work fine for you. There are two things that I would say make a 5th wheel needed: length and hieght. If the trailer or tall is long it needs more stability to aid in keeping it from twisting. A 20' trailer will be fine unless it is 12' or tallers IMO

 

No matter what trailer you get, get the B&W gooseneck hitch, and then for 500 or so more you get their 5th wheel adapter, that slips into the gooseneck hitch pocket.
It would take a couple of minutes to stick it on when you need it. And when you don't you have full use of the bed.
http://www.topratedadventures.com/Mf...lerHitches.htm

 

I agree with icrman the B&W is the way to go. I got my Companion hitch from Radauto off Ebay. $567 with free shipping. Got it in 3 days. With this system you have the best of both towing types.