92 rocker panel replacement

Hey everyone,

Ive had you guys solve two problems on my new 92 PA, so I figured Id throw this out there and see if anyone can help.

My cars rocker panels are rusting out, the passenger side is so bad I think it'd need replacing (driver sde is rusty but not as bad.)

Ive seen some replacement ones on ebay and online, but how would I go about removing/installing them? The old ones are part of the frame of the car, and I dont think the clearance between the doors would allow for me to layer the new one on the old one.

Heres one Im looking at:
http://www.rustrepair.com/REPAIR_PANELS/onlinecat.htm?r=fr&p=SM-BUICK-PARKAVE.85-679142L

So whats involved with this kind of repair?

thanks,
Josh