Not familiar with the US-based magazines, only buy a copy of R&T every couple of years.

You should definately check out Winding Road, a monthly magazine available in pdf.

For me personally, I would consider some British mags apart from the above mentioned German magazines. By the way, SportAuto just launched their online appearance , incl. a hotlap documentation of the N'ring Northloop & the Hockenheim track. Only in German, I am afraid.

Greetings!