That's not going to be a tire issue. 3000 miles and there's still a swaying issue?!?! Iit's going to be in your alignment or hard parts. If you had that alignment done at the same time, I'd wager that's where your problem is. Just because you paid them for it doesn't mean it was done right.

I see too many of these that need adjustment..... Thursday I had an '07 that had just come from the Dodge shop(they had it on the lift to set it!!). Literally been driven 35 miles from the dealer and still hunted all over the place down the highway... . When I got under it with my tool, it was
7/8" wide in front off the tires. Jacked up, spun the tires, looked true, so I set the toe in off the rubber crown on the sidewall. Told the guy to drive it and try it. He calls me 10 minutes later, says it's perfect. Hasn't driven this good since he bought it.
Not saying I'm that great, just that some of the "professionals" out there are
not that great.
The MTs will wander a
little on really rough roads, I've noticed. But on good highway/interstate, they drive as straight as anything else. I'm sure it's got to do with the big sidewall protectors catching pavement... .