Help with SDA1 tweeters

Hello i'm new to the Polk forum, i have recently acquired a set of SDA1's The first gen. I have a bad SL 1000 tweeter. I called and talked to a tech at Polk and he told me that in order to install a replacement tweeter, the RDO 194 i'm assuming, i would have to modify the cabinet?or mounting holes? as they are different size than the Peerless style? has anyone ever ran into this? I have swapped in a black Peerless out of my Monitor 7, for a test, it fit perfect. he recommended getting a replacement from another speaker company in the mid-west. I haven't run across anyone talking about the actual physical dimensions of the tweeters or the mounting. Maybe i was misinformed? Minor cutting or drilling some new mounting holes is no big deal but i would prefer not to. Any advise or tips on these SDA'S would be appreciated. I know they probably need some crossover work, i'm already lining that up, they still sound pretty good.
Comments
You might be able to find a working peerless tweeter on eBay or even on here.
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They sell on eBay also. Here you go
http://m.ebay.com/itm/Peerless-Copy-8-ohm-Tweeter-Good-Replacement-for-Polk-ADS-Speakers-MT-4115-8-/150364380186?nav=SEARCH
F1nut is correct the original peerless crossover was a bit different. Plus the cut out for the sl2000 and rdo194 is different than what you now have. You will need to file out a bit on the sides of the oval so the new tweeter Connections do not get pinched into the magnet. You can fit the rdo194 with some routing and hurricane nuts.
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