The "baby M's" of the 'X' family just got a bit more big brother like. With more volume and a deeper, more aggressive note courtesy of the Dinan axle back exhaust system, the F97/F98 now stand on the precipice of rivaling, or even surpassing, its V8 siblings --- at least, in regards to sound. With an intoxicating and menacing sound befitting of a high performance SUV the X3M/X4M holds its own amongst the pantheon of more traditional M's. In order to achieve the deep and throaty signature Dinan sound the system incorporates larger 76mm tubing (vs 70mm stock) that allows freer flow through the entirety of the system but specifically to both outer pipes when the enlarged valves are open. The resulting flow and sound mimics an awe-inspiring straight pipe solution with a deeper, fuller tone, a defining element of all Dinan exhausts. In contradiction to the aggressiveness resulting from open valves, when the valves are closed, all gasses are forced into the muffler for sound deadening and exit the two inner tips. Regardless of valve position, the intimate nature of the interior is retained so conversation can continue without an excessively loud drone courtesy of drone abatement technologies housed within the can. With the Dinan exhaust equipped on the X3M/X4M you get the best of both worlds; aggressive tone/sound and civility Perhaps equally important to the sound of the installed Dinan axle back system are the resulting aesthetics. With a nearly perfect symmetrical design, the raw muffler and pipe routing are pleasing to the eye even when the matching proportions are only partially visible after install. The piping culminates into four massive 114mm (4.5") tips that fill up the previously spacious factory cut out in the valance without appearing to be oversized and unnatural. The imposing tips utilize a new tip design with an inverted clamp neck. The new style allows for two very important things to happen. The first is the ability to have a longer tip sleeve length without sacrificing real estate for a clamp neck thus allowing larger tips even when there is limited straight pipe to clamp on to. Secondly, the interior clamp neck means that the clamp itself is almost completely hidden from view for an unblemished install. Dinan has retained its signature straight cut tip design, safeguarding its unique and elegant styling position amongst a crowded marketplace full of angle cuts. With systems available with either black ceramic coated or polished clamp-on, and laser engraved exhaust tips, there is a version that is sure to meet your individual aesthetic needs.