Just got one and it's about half the size of the stock one regarding width/thickness. Is that right??

 

If it's a drop in filter it better be at least as long and wide as stock so as to completely fit into the air box and not leave any gaps. I suppose the thickness might be key as well to ensure that it's held in place properly but I can't be sure.

 

It's exaclty the same dimensions as the stock just not as fat.

 

Then it should work ok. there's a lot of debate about the K&N's these days. specifically do they filter out enough potentially harmful particles etc. They require a bit more care and don't really add much performance by themselves. I run a round one on mine and I'm going to be adding a nylon prefilter to keep it cleaner longer.
OBTW, you wouldn't be anywhere near Boston would you?