To remove your seats, you just unbolt them (brackets and all) from the floor. There are two bolts at each corner at the front and back of each rail. Just slide the seat forward and back as needed to access the bolts. Should be a pretty easy opperation. I'm just completing the body work on mine and getting ready for paint. I used POR-15 on the floor pans, in the trunks, engine compartment, and on the front and back under the bumpers. From what I can tell, this will stop whatever rust was left after heavy wirebrushing to bare metal, but I cut out and replaced anything that was heavily pitted or all the way through or getting thin. My floor pans werent too bad, but I think I would at least want to weld in new sections if not whole new floors if they were too heavily rusted (ie, all the way through or getting thin). POR-15 stops rust progress and should inhibit new rust, but it does nothing for structural integrity. The only thing between your but and the pavement is that floor, so it should be sound
You can probably find used sections from parts cars that you can cut in as needed fairly cheeply (I got a passenger side firewall section for mine for $30 from Dave at GPR). As for the area under your battery tray, I can't tell if it's structural or not from your pic. If it's just the part that goes around the engine, that's not a big deal. You will need to cut in some new metal there. But if the wall is that bad, especially the lower part, which is that back part of your rocker structure and suspension console, then you have bigger problems. That will need careful repair. It probably is safe to drive to a shop as long as it's not too far away and there aren't a lot of big pot holes
Again, depending on the degree of damage, it may be relatively simple to fix by cutting in new metal. All the parts are available from various sources. Auto Atlanta should be approached with great caution; however, I've had nothing but good experiences with Pelican, GPR, and Restoration Design (
www.restoration-design.com). Again, don't overlook used body parts. There are lots of chop cars out there with good metal that can save you a lot of $$.
Here's what I started with in December for my 2nd 914 resto (purchased from Dave @ GPR):
I'll be painting within the next few days. Here it is about 6 weeks ago after the first primer filler for the parts that were done.
Finally, an example of cutting in a new piece (in this case, fabricated myself).
Hope this helps! Good luck and have fun
{DD--edited to try to get the images to show instead of links}