Janis Subwoofer Help

Okay, I'm buying a classic Janis Subwoofer from a gent near where I live. Unfortunately, when he went to test it, he noticed some problems in the sound of the sub. I think that the surround has rotted, but if you're aware of how the old Janis subs look and work, you can't see the driver, and you can't easily get to it either. So here's my issues:

1. If it is the surround, can this be serviced? I've read that this sub is VERY difficult to open.
2. If the sub can be opened, can the surround be repaired?
3. If not, can another driver be used?
4. Basically, I need to know as much as possible about these subs, so ANY help will be appreciated.

I'd love to get this sub. It is a bee-utiful piece of woodworking, with serious WAF, so I'm willing to fix if it is a reasonable undertaking. Problem is, I don't know....

Thanks very much!
Owning a pair of W3s and very familiar with the model 1, my understanding is that John M(Janis designer)used JBL pro drivers. I have never known a Janis unit that had a deteriorating driver,unless it was not in a proper environment. Can you tell me more of the "problem" ?
Unfortunately, I can't at this point. I don't yet have possession of the sub. I had purchased it via eBay from a local gent and before we did the handoff he did some testing and noticed some oddities in the sound. I'll try to get the quote so I can be more specific. This is why I'm trying to figure out what to do... :( He's willing to drop the sale since he didn't notice this before, but for $200 I think it is probably worth taking a shot. (That's the price he's dropped the Interphase 1A and sub; I think it is the smaller Janis). OTOH, I'm kinda ignorant here and it might not be worth it at any price. So I'm just tossing this out there looking for advice.

A very nice gentleman has offered to send me some docs and told me how to contact John, so I'm hoping that this will yeild some good info. However, any help is welcome!!!

You can't have it both ways - a dirt cheap price and a guarantee of what it's going to take to fix. At $200, I would buy it and take my chances, but I don't know what your finances are. If $200 is a lot of money to you, I wouldn't bother. I do believe the driver in the Janis was extremely cheap, not to say the speaker didn't sound good it just used a cheap driver, so if that's the issue, it shouldn't be expensive to replace.
If you can get into the cabinet the driver should be fixable, especially if it actually is a JBL pro driver. Re-cone kits for JBL should be readily available. If Altec is still in business re-cone kits should be available for them also. Sounds like the trick with the Janis is just getting into the cabinet, doesn't sound like they were meant to be taken apart. You might want to google speaker re-coning and consult with a cabinet maker.