Don't think you can get away without and amp.
A lot of people buy the ms-8 and find it just won't do the
woofer under the seat and its not a lot of drive for door speakers either.
The Morels are probably the best door speaker but there are fitment
issues with the coupe , some have solved this but I don't know how.
The ms-8 is used a lot here as it flattens the bad eq in the
head unit but you can recode the head unit in most cars to be flat to.
Indeed even some of the ms-8 users do this because they say it sounds
better. The ms-8 was accepted by a lot of the logic 7 owners as the best
way to get a lot of channels to fill the hole left by the 9 channel L7 amp
and still have logic 7 . It does allow you a lot of control over your sound but you have to do a lot of tweeking or can do a lot tweeking to get it right.
Base system solutions are fix the eq , add amp and speakers if you want you
can add a processor.
http://www.e90post.com/forums/showthread.php?t=641323
Jehnert are the most accurate under seats they also make a direct
fit three way set that has a 4inch and tweeter for the doors that fits in the coupe.