Always a good idea to disconnect the battery when installing anything electrical. One, reduces risk, two, resets DME. It's very easy...10mm socket and disconnect negative terminal in the trunk.
First...take logs and see what your trims, AFR, and fuel pressures look like.
Second, swap coil packs and see if the problem follows. If it does, change coil packs, if it doesn't...
Third, swap plugs and see if the problem follows. If it does, new plugs, if it doesn't...
Forth, swap injectors.....
2008 AW E88 Auto
BMS BEF (w/Cobb), G5 ISO, SLD, CPS, DCIs, & OCC--
M3 FSB & FCAs--
ER SS brakelines--
Stoptech slotted rotors w/Ferodo pads--
Apex Arc 8s wrapped in Michelin PSS Future upgrades:
Wavetrac LSD TBD: