I've got AR woofers that have square magnets and some that have round magnets. I've never run them on test equipment to compare them, but i'm sure that there are differences in them and not just because of the magnet shape. Technically speaking, one is better off with a bigger round magnet than a square magnet. Whether or not this works out to be true for these specific drivers may be another story.
While i've not used them, i've only heard phenomenal compliments about Millersound. They seem to be very up on the technical aspect of driver repair, so if you want to get some drivers repaired, that might be a good phone call to make. Stephen Tidwell at Layne Audio is a favourite amongst AR devotees, but i don't know how "OEM" the drivers are after he gets done re-foaming them. He is very fair in terms of price, but i've heard that he's been very hard to get ahold of lately. Sean
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