The original transkit required you to either use another kit's breathers or purchase the machined aluminum breathers. No doubt the cost of offering aluminum breathers requires you to offer resin breathers.
The AMT kits have been out of production for years. Revell/Monogram periodically offer some kits. I think the Mack fire pumper is still available. I have heard rumors that the the Peterbilt 362 is due to be re-released shortly.
Definitely have check that place out if I ever venture in that area. I have found some rare kits at almost give-a-way prices at out of the way hobby shops.