I removed original parcel shelf and put in loft, then made an mdf shelf and covered in acoustic cloth, fitted a set of 6x9s underneath so all hidden.
Then bought a spare set of front doorcards and made up some rings the size of a set of 10" speakers and covered in acoustic cloth.
All speakers are powered by 2 powerful amps, gives a really good sound.
All blends in as I have black leather in mine.
But can return to standard whenever I want.
Hope that helps