False positives should be filtered at the sensor. If the sig being falsely triggered does not apply to any protected system, then the sig can be disabled or even retired. Otherwise, just filter the src or dst ip or network as applicable.
I believe you are going to need to filter on both devices. I suggest tunning the sensors lightly - only tune out the obvious issues that you never expect to be a problem. Then I would see how things go with your network and the MARS and do any additional tunning on the MARS. Tunning on the MARS is very easy to do and the tunning can be quite specific (specific hosts, protocols, devices.. etc).
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...