We also use America's Tire. Great prices, service, and warranties.
I found no need to tweak the sport suspensions (E82 & E90) when switching to non-RFTs, although I did pay for realignment at Crevier BMW. The one BMW I had with standard suspension (E39), I quickly swapped with aftermarket bits (I am a fan of the Koni FSD dampers).
No, you get no credit for your new RFTs which is why we drove them until they were worn.