I have the Harman Kardon speakers, are they much improvement over that would you say?
The HK speakers are an upgrade in name and cost, more than actual sound reproduction. From testing I've done on HK speakers, the HK were only slightly better than the standard speakers. The sound can be bettered for less money, by using another speaker manufacture. I chose the JVC CS-J620X I fitted because they sound good on a budget. I've not tested the HK VS the JVC directly, but to my ears and the tone tests tests I've done, they're good for the modest cost (under £20) of them.
It should be kept in mind that a car door is hardly a good speaker enclosure, so will need improvement for speakers to sound better.