Yeah...I was looking for LSD and all the leather has it from what I have seen.

 

You could always expand your search to non-LSD cars and have one added later. Even having someone else do the labor should clock in at less than.. what, $1k? And then you'll have an open diff to sell and make a few bucks back.

 

If you can afford an '06 NC, then you can afford an MSM.

Both cars have around the same power. However as others noted they are VERY different cars. You should try to drive both and see which you prefer.

There's also a school of thought stating that an inexpensive NA + a track session with instructor will make you just as "fast" as you need to be around town. Remember, while going fast in a straight line is fun, that isn't why people buy a Miata.