Thanks Russ, John and especially Mac.

The door and parcel shelf are indeed new Kenwood items, 6 inch 3 way in the front doors and 6 by 9 in the parcel shelf. All 4 Ohm. Head unit as stated. I am confident that the head unit and new speakers are fine for compatibilty with each other. I also constructed a subwoofer for the trunk around a Polk 8' bass driver (and powered it seperately with a dedicated power amp). No complaints with the result so far until the tweeter install of yesterday.

I did call the shop where I bought the tweeters for advice (an electronics type store, like Radio Shack) but the counter jockey was even less au fait with electronics than me. I may actually go in today and enquire further. Maybe an alternative crossover is an option.

Thanks again.

J.