Have you been over on ktmtalk.com? Lots of threads on LC4 exhausts including quite a bit of info on the tradeoffs between these two.
The cliff notes version:
The enduro muffler makes similar power to the stock supertrapp, sounds about the same, looks a lot better, and weighs about half.
The supermoto muffler offers modest power gains (if jetted properly), is quite a bit louder, and might get you in trouble if you're riding in the woods without the spark arrestor.
I went with the quiet pipe. Actually, I'm waiting for it now - it is backordered.
Where'd you get the idea the enduro costs $125 more? According to online pricing, it's $30 less.