I'd pay up to $120 for it if it was in MINT condition. It looks like it has a chip in the top right part of the ring - need a better photo. Used condition with minor damage I'd say probably somewhere between $50-$80. Just my opinion, if that sounds fair send me an e-mail or pm. If not it will be interesting to see how much it fetches on eBay.
On the other hand, there was a complete grille on ebay with the "S" badge for $20 just a few months ago. I would have bought it but it was in Melbourne or something and it was local pickup only. The seller probably didn't know there was a difference.
Cheers, Shane.