No worries about the 6.0 it is different from what is in the F250 and F350's. We purchased our SN from Lazy Days 2 years ago. Lazy Days will deal so work it, they will come down on the price to get the sale especially if they fly you down there. We went down to look at a Class A pusher but the wife didn't like the interior colors and that ended that. Our salesman was Jason Brunner and he was top notch, loaned us his toad to drive around while we were there, picked us up at the airport and took us back to the airport then picked us up again on his day off when we took delivery of the motorhome. The wife and I love ours but it has been a learning experience since this is our first motorhome. The main thing I would HIGHLY recommend is finding out if the brake controller has been replaced and find out when it was replaced. If you have done any research on the SN's is brake controller issues. We left Lazy Days and went to Key West and spent several days. On the way home the dash alarm went off, the low brake pressure light came on, the ABS brake light came on and the main brake light came on. It was a bit unnerving not knowing if the brakes were going to fail at any minute so we ended up spending several hours on the side of the road waiting for road side assistance then decided to try to roll on and ended up at a small truck repair center and the guy ran diagnostics and couldn't find any codes. While stopped I googled SN Brake lights and BOOM!..there were countless stories of the same experiences we were having and everybody said brake controller had to be replaced. We did buy the extended warranty and that was a nightmare getting it fixed correctly and it took 6-7 months and several hundred dollars out of my pocket because the warranty people kept saying it wasn't the brake controller...a major PIA but we finally got it fixed and no issues since.
I pull a 28 ft enclosed hauler with a 3800 pound show truck and the SN tows great but with that being said I would recommend replacing the hitch bolts. On the way to Daytona last year going down 95 the hitch came off, sheered every bolt except one.(was towing our older 24' enclosed steel frame hauler with the same truck) Got it bolted back up but the the road side assistance guy brought grade 5 bolts so it was a pucker fest the rest of the way down but the first full day I replaced them with grade 8 bolts and torqued them down to the correct specifications. After talking with a buddy we came to the conclusion that the hitch was installed improperly and the bolts were over torqued, probably with a impact wrench and were stretched. No problems since replacing them with the grade 8s.
Check the date on the tires, same Daytona trip but on the way home we had one blow out and it ended up being the tires were very close to their change dates, 6 months out so I'd make sure you have good tires.
The SN's are nice motorhomes, I am still worried about the brake controller because I have read of people replacing them then 2-3 years later they go out again. This isn't a Gulfstream issue but a International issue that they claim they haven't heard of but its well documented and the same year and model of frames that were used for School busses had a recall on the controller but only school busses.
The factory LCD tv's suck so I replaced them with 32" LED TV's which are much better and were extremely easy to mount in the old tvs locations.
Good luck with your decision, when they are rolling they are great but when something goes awry they can be a pain in the butt.
On the side of the interstate with hauler in tow