I've now had my Dinan S3 for a year, and I was able to get mine using non-Dinan OC and FMIC (I have ER and ETS units). $400 to upgrade and a HUGE difference from S2, especially with the Dinan Free-Flow exhaust and CF CAI. Never a problem at the dealer, even though I'm completely out of CPO warranty. OP - congrats on your upgrade, and enjoy! And as far as the Dinan-knockers on here - "Illegitimus Non Carborundum"!
2013 F30 335i M-Sport 8AT/MPE/MPPK, 2016 228i M-Sport Cabrio 8AT