Whilst looking for rss feeds I came across an American website called Racer.com, for a magazine of the same name. This also happens to be a Haymarket publication, like Autosport, and all of the content appears to come from them. At the bottom of each article it actually says ‘This article originally appeared in Autosport.com.’
The website seems to be up to date and I prefer the layout to Autosport’s cluttered home page. Obviously the American racing series are more prominent, but they also have sections for DTM and other European racing series.
After a few page views a box does appear prompting you to register, but you can dismiss this and continue viewing. Alternatively, registration is free and just requires you to type in your email address, password and select which state you live in. No other details are required.
There does not appear to be any restriction on the number of pages you can view.
I hope this information is of some use.