I am sorry to hear of your problems. Sunny Brook used to build a good quality RV. but it appears that they are suffering from the same issues as others...lower cost, cut corners and worked that have never heard of Quality Control.
Lippert has been having frame problems for several years now. i am surprised the the frame did not come from Lippert with the suspension installed.
As for tires, When I looked at the Bristol Bay, the first thing i noticed were the tires looked woefully inadequate. When I looked at the tire load ratings, they were barely adequate fro the axle capacity.
Since they are having to do suspension work, it may be best to go ahead and upgrade the axles and or tires for a higher capacity rating.
And glad to have you here on iRV2.
Amateur Radio Operator (KE5DFR)|Full-Time! - 2012 6.7L Ford Crew Cab Dually -2013 HitchHiker Champagne 38RLRSB - Travel with one Standard Schnauzer and one small Timneh African Gray Parrot