I like the aftermarket heavy duty front drum spring retainer also.
For the rear servo, I have used both the "billet" 1-piece units, with heavy duty (thicker) spring retainer;
and also the "billet" Sonnax type replacement piston and still used the factory inner part, but shimmed the spring solid.

Link to Sonnax web site
Part No. Application OE Part No. O.D.
22912C 47-48RE '97-Later 52118745 2.46"
22912B 47RE/RH '94–'96 4531229 2.46"
22912 46RE/RH, A727 2801281 2.80"


Sonnex_RearServoPiston_22912.jpg
1993 Daytona, 5.50 at 130mph (1/8) 1.19 sixty ft (PG). Link to 572 B1 - Part 1