Shopping for new Tow Vehicle and Fiver - Doing homework

1. Get the factory hitch prep. Makes installing a 5er hitch so much easier.
2. 18" is what I bought. 20" replacement tires are too pricey for me. No advantage to them other than looks. Choices are more limited in the 20" tires too when it comes time to replace. There is a 1/3 of an inch height difference between the 18s and 20s so almost nothing. The 20s are taller.
3. You could buy a sliding hitch if you want, I don't have one, and don't need one in all but extremely tight turns. Up to you if you want to spend the extra money.
4. I get invoice pricing through my employer. You might too. Check into it.

Other notes:
The 2500 I have has just over 3000# payload, the 3500 SRW would be about 700# higher, likely about 3700-3900# or so, depending on how fancy the truck is. Mine is loaded.

The 2500 has rear coil springs, the 3500 SRW has rear leaf springs. The 3500 will ride a little stiffer when empty, but does sag slightly less when loaded.

Videos of 2500 vs 3500 SRW diesel:
LINK

Thread where I compared the suspension squat 2500 to 3500 SRW:
PART 1

PART 2

PART 3

Another thread where I have window sticker and pictures of factory hitch prep package:
LINK