That's a difficult question to answer as it generally is that last combination I run, as R3E is the only sim i use these days, and that would be Group C at Road America.
If we're talking the new content, I'd suggest the 964@Most and Group C@Paul Ricard.
Otherwise there's the TCR18@Mantorp Park, FRJ@Red Bull Südschleife, DTM92@Mid Ohio, NSU@Brands, BMW235i@Monza Jr, AudiTT RS@Imola.
And of course the Porsche Carrera Cup anywhere.