I have 2" HBS spacers 5100s in mine since about 1k on odometer. It threw my axle off about an inch. Ended up buying the Thuren track bar to fix it. AS far as DW i have not seen any idications of it 10k miles later. But still tense up down on certain stretches of highway. Always in the back of my mind.
If it were me I would install them so I could fit the 315s. 285s look too stock for me.
Or try the 315s on first and see if you can live with the rubbing. Before I leveled I had 295/70-18s (~34.2" tall), and it had a minor rub at full lock. I had no plans to level but it annoyed me.