Having heard them all three, I would personally rate them in this order(from'worst' to best: PM7001, PM7003, PM8003 and PM7001KI.
There's not much between the 7001KI and 8003, but the first only edges it, it sounds just a bit more detailed and the bass extension sounded slightly better.
I couldn't tell much difference between the 7001 and 7003 to be honest, so if you can find one for a bargain price I'd go for that, if you can find a 7001KI for a bargain price I'd wholeheartedly recommend that one.