New here!! Looking to buy an S4 I currently have a Boxster S (puts on flame suit

I'm selling the porsche because i need something a bit more practical....
S4s seem excellent value for money, reliable tunable practical etc etc. My question is this...my friends and I are soon taking our annual pilgrimage to the Nurburgring, my buddies own E36 and E46 M3s and one has Porsche 911 (964 variant). Last year I had a BMW M Coupe (breadvan) so it was the fastest on the autobahns (only just though).
How much will I need to tune a standard S4 to keep up on the autobahns/ back roads? Will an MRC remap plus gutted pre cat be enough?? I'm thinking I still may struggle.
I'll thrash them when we get there but dont want to be the rear gunner on the way.....
You lot seem very informed, can you give me an idea?

Thanks in advance...