I did replace my factory OEM hitch with a Reese Titan and I use the Reese 41" extension. I had my trailer custom made in all aluminum with electric brakes. I haul a 1400 lb Yamaha Rhino. Just be careful about using the factory hitch. I replaced mine after one of the forum members warned me that the welds on his factory hitch started to fail while using a long extension. There was no comparison when I removed the OEM hitch and laid it beside the Titan.
2009 Silverado 3500 dually D/A, Supersprings, Stable Loads, Bilsteins, Hellwig Sway Bar.
2010 Arctic Fox 1140 DB, 220 watts solar, custom 4 in 1 "U" shaped dinette/couch, baseboard and Cat 3 heat, 2nd dinette TV, cabover headboard storage, 67 TC mods