Just do it. You could be waiting a long time. If I had to choose, I'd stay with the thump to keep the drop. You can always revert back to stock should there be a opportunity to fix the thump sooner.
F10 30 Jahre M5/F80 30 Jahre M3
F82 M4 GTS
E36 M3 with S54 Swap/F22 M235 Dinan Stage 4
X15 X5 3.5i/03 Cooper S (Maxi Tuned +50bhp)
60 Impala (43k orig mi)