In support of what kaigoss69 did with the sub and the MS-8, I have experimented quite a lot with different MS-8 calibration methods in customers car and what I have noticed is that the underseat woofer location in our cars may be the real culprit of this apparent lack of midbass of the MS-8.
The last customer setup was really a revelation as it was the very first install where there was no sub as part of the install, and that the MS-8 set up to power all the speakers in the system (aftermarket front and rear while keeping the OEM HiFi woofers in place). This system got some nice midbass from the get go, no need to bump the MS-8 EQ bands but it require some increase in the bass adjustment as there was no aftermarket amp gain to adjust. Calibration volume was -26 -> -30dB.
My take on this is that in our cars I think that kaigoss69 idea will simplify a lot of MS-8 installs for those that really want to do the least amount of tweaking while having strong midbass from the get go.