duraflex / fiberglass / FRP (fiber reinforced plastic) are all the same thing. its quality stuff for the most part, and it's much more flexible than say.. a classic corvette body.

in my experience with dozens of body kits over dozens of cars, it'll require some TLC to make it fit just right; nothing ever ever fits like OEM. the hardware kit it comes with is probably decent, and would most likely require you to drill the holes and insert the locking plugs that's probably shipped with them.

you most likely wouldn't need to make a trip to the dealer for hardware, unless you wanted to order C36 weatherstrips for the doors since the skirts will make your stock ones much more noticeable (black rubber edge along the bottom of the doorline).

thats not a bad deal to be honest, and for that price it's probably a decent product imported from the far east. good luck on it, and keep us updated with the install!