Excuse me for sounding like an idiot. Still new to this Ram stuff, I'm headed in this same direction as OP, now so you use the Bilsteins in lieu of the spacers provided with the zone kit? Also if stock 20" wheels will be used with 35" tires what spacers would be needed? Thanks in advance.
As mpittman already stated, you need to use the Zone 4" strut spacers AND the Bilsteins together.
You need 10mm spacers at a minimum to run 35x12.5's on stock wheels. However with the lift I would recommend going larger for a wider stance. That will look more proportional for the lift height. For either option, check out Motorsport Tech as they're the brand you'll want to go with.
I'm going to run 1 ½" spacers with my factory rims.
I think I could get away with less but I want the tires to stick out a bit.
So a 6" lift with 3" coils would be pretty much be the same as 4" with 3" coils with bilsteins?
1.5" is the minimum you want to run to avoid having to trim the factory studs so that's a good option. The 1.5" spacers will essentially make your stock 20x9's a -19 offset which will be a good stance with the lift height.
That is correct, they're almost identical height wise. a 4" lift with Bilsteins at 1.4" will put you at 5.4" of total lift. A 6" lift by itself is 5.5" of front end lift. That being said, a 6" lift does still come with different components than a 4" lift.