That one could be difficult, as I believe the factory Harmon Kardon speakers are low-ohm ones. The 6.5" woofers in the front doors require a spacer for aftermarket ones, and the tweeter separates are an odd mount, so it might require some custom labor work to get new tweeters in place.
As far as brand, if you've got a high enough budget, go with Focal.
This post was edited by Surfpunk on Mar 18 2017 03:44pm