I figured I'd share this. I recently purchased a 06 MR and it came with a Perrin 2in antenna. It had decent signal but wasn't as good as stock. I've read people using S200 and Element OEM antennas. I highly recommend purchasing your antennas from Mangwalk.

http://www.mangowalk.com/

I've purchased antennas from them in the past with very good results! I should also mention you can swap out the base screws, which come included. Should you ever change your car you can put your stock antenna back on and swap this to the next. I paid 12 for mine and it took 2 days to arrive.

Note: You will need to trim the screw 1/4 in so that it can sit flush when mounted. This took me 5secs to do with a Dremel Tool.

 

just ordered me one

 

Awesome, I had one on my BMW but I lost the stock antenna. It's not as long as the stock antenna and is similar in size/style to the S2000 OEM.