A nice clear detailed review
@SteveCole
I opted for the Bilstein set-up myself, but that was simply because the alternative at the time of my install in 2017 had slightly more inconsistent reviews, where as the B14 never seemed to have any reliability issues. Plus as a work vehicle that has now covered 70k on the B14s, carries heavy weight all the time and is driven enthusiastically, they are still performing as good as the day they were installed 2 years ago.
The main reason I never went down the 'Air' route was purely because I was constantly reading about issues with bags and pipes and general reliability problems. This for me was too much money, and a constant worry that I might jump in my van at 4am to shoot off to a job, and it be stuck on the floor. Couple that with a diary that is full of work, and no where to move customers to if anything went wrong, and air was ruled out a long time ago. (though I do love the concept)
Would I go for the B14s on my next T6? Well the simple answer is no. Not for any other reason than i'd now opt for the Solow set-up. They are running the same brilliant Bilstein shocks, but with the extra room to go lower, or at least sit at my height without being on the max settings.
Things hopefully look like they've moved on quality wise, and at the prices you've paid, i'd of certainly looked at the Stance coilovers, and others. So I totally get why you and others might go for this option and I genuinely hope that 70,000 miles in, they are still performing like new. This might in time force the higher end shocks down in price because I agree, the difference between Bilstein and the others is quite considerable, but one cannot help but think there is a reason for this. Only time and distance will tell
Next on your list should be uprated anti roll bars and I speak through experience, get yours to a Hunter dealer, and get it 4 wheel aligned. There is a brilliant place near you in Hinkley that many of us have used, and they know the VW Transporter very well.
Welcome to the forum.