Upgrade to B5 S4 Master Cylinder?

Wed Apr 28 20:25:03 EDT 2004

Is there a significant difference between the 1998 A4q MC and a B5 S4 MC?  
Would it be worth it to upgrade my 98 if I go to bigger brakes?
Thanks,
Craig K. Porter
'98 A4 Biturbo Quattro  Stage 2+, Xenon Euros, H&R coilovers, , UUC VM3, APR 
downpipes, RS4 bumper, DVD Navigation, Sirius satellite radio
'70 914 1.7l  Flared, 5 lug conversion, 19mm MC 