They are pretty nice. I got the widest ones they had. They come with a wire stiffener that can be inserted into the outer lip to keep them in shape once installed. If trimming the fenders, you will need to build up a flange inside the fender opening, since they need to be screwed or riveted into the inner lip of the fender. Another thing to note is that they prefer to install into nice even curves. I had to open up some of the more squared off wheel well openings on my '85 to make them fit better. Here is the first fender trimming I did for the front:

Before shot, lower fender is trimmed but no lip:




Added lip insdie lower fender and smoothed out the front curve:

I was looking at the flat surface type but I'm not too sure that's going to work well. I think I might have to make a fender lip like you said. Problem is I really have no experience with body work so I don't think it will be very pretty.

I am curious to see your results 4crawler. How soon do you think you will be installing them?
Thanks
(always looking forward to a 4crawler write up) <img src="/forums/images/graemlins/cheers.gif" alt="" />

I need to finish cutting the rear fenders. They will be a lot more work since you are cutting into the interior sheet metal on the 4Runner. Need to round up the right sheet metal to fill that gap back in and to form the lip for the flares to mount to. Hope to get to that before winter, since I have some rust holes that are see through already. I plan on using threaded inserts for attaching the flares. They install like pop rivets into the sheet metal. Then you run screws through the flare and into the insert. Should make a fairly secure attachment and still be removeable easily. I want to keep an eye on any potential rust. It was my old Bushwacker flares (that are riveted on) that led to the rusted holes in the rear fender.