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Michael, I just changed up from my old Mangels to the Mobelwagens.
I'm swing axle, so the 5.5" rims presented no clearance issues. And coincidentally, I just went to 175/70 tires, too (Vredestein Sprint Classics). If I recall, the specs on the tires said they would fit down to a 4.5" rim. You can check the full specs on Tire Rack's site. Just click on any tire and there's a dedicated tab with full specs.
If you can have the rims adapted for $250 per, that would give you more options for tires in the future, and certainly less hassle and cost than suspension mods.
BTW, if you're buying from Mobelwagen, they seem to offer decent sales pretty regularly. Their normal price is around $170, but the sale price this past July was $135 and I think they ran the same sale pricing about six months earlier for about a month.
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