HD Leaf spring w/overall lift and high towing capacity

Heya!
I'm having a hell of a time dealing with the Toyota service depart here on Vancouver Island.. I was under the impression the truck was stock when I purchased it, but, evidently, it is not. For the past year I have been towing my 7000lb travel trailer on deflated and cracked airbags, which ruined my leaf springs, of course, and whatever else...sooo...I am in the market for new leaf spring packs. I have ordered new firestone airbags and daystar cradles, but need some advice for the leaf packs. I do have a WDH, but couldn't ever figure out why I had so much squat still - hmm!

The truck is 2016, 5.7L limited, double cab (90,000km) with Bilstein 5100s (front set at middle notch). I am unsure of the condition of the shocks and other suspension components; but the truck squeaks over any minor bumps and is progressively worsening. The dealership says the leafs are fine and the warranty wouldn't cover any damage from aftermarket parts anyways- however, they also insisted that the shocks were stock when I called them last - anyways, no point in venting any further - I had a mech at a susp shop check them out and he said they are completely shot, and I'll need new sets. I have done an extension amount of research on the truck the past couple months, but everything I try to order (as per these forums), doesn't seem to be avail in Canada. Its generally names I do not recognize, other than Icon, but that is completely out of my price range. In fact, I was thinking I would attempt the suspension upgrade myself; well, I was only going to start with the airbags and cradle; irregardless, hoping to get advice in the following:
1. I was thinking the Dobinsons L59-121 (heavy duty, 5+2) or Deaver u748 to give me the 2" lift in the rear - have yet to find any dealers that carry they parts in Canada!
2. With the Bilsteins currently on the middle notch in the front - I get the impression it is not advisable to raise it to the top with the large towing weight (32 ft TT, 5k dry). Is this correct?
2. Overall, would like a 3" lift in front and 2" rear; and accommodate 33-35" tires. What are my options?
3. I want suspension that is suitable for off-roading as well.
4. I am waiting to hear back from a couple shops in regards to options, but maybe someone on here has a suggestion as well? Would my 5100s be hooped (they dont seem to be leaking but lots of corrosin on the rear ones)? What other components would I want to replace or research?

k - thanks for reading this long ass post!

 

A quick search on deavers website shows this business as you closest distributor. Might be worth a shot to reach out

Baja North Enterprises
615 Dairy RdKamloops ,BC V2B8N5CanadaDirections
Phone(250) 572-5654Fax(250) 579-8748