Drivers for older ProAc s

I own a pair of ProAc supertowers and the drivers are shot.I have two cats!! Any ideas on where to get economical replacements.I think they are a metric size driver.Somewhere in the neighbourhood of six inches.Thanks for any help.
If they are the same as the Studio 1s, you can get replacement drivers directly from ProAc. I think they cost me around $100 a piece. Otherwise look in check with companies like Madisound who sell raw drivers.
US distributor for ProAc is Modern Audio Comsultants ph 410-486-5975, ask for Richard. US prices are quite fair, esp compared to many other imports(B&W, etc). has drivers and croosx components. goerge is very up on these things.