The issue that I've ran into is an initial rough idle during cold starts, but it smooths out in 5 seconds. The car runs noticeably smoother and stronger with the E25 blend, and it may be my imagination, but it sounds like my stock exhaust is more noticeable inside the cabin too (probably due to being able to hit the max timing tables).
'15 IS350 F-sport Ultra White/Rioja Red
'09 E90 M3 7-DCT Interlagos Blue/Novillo Silver
[MS Pullies|K&N drop-in|Test Pipes |Evolve Stage II tune|Evolve Servotronic Map|Evolve M3 GTS-DCT file]