If you're looking for a bolt on kit, Iana has the best setup I've seen. That said, there's very little wrong with the variety that S111 sells. I don't think there's a documented case of the inner links breaking w/ the S111 solution, so your easiest bet is to simply go with that, IMO...
The solution John posted isn't great for most as it won't be very easy for you to duplicate without spending bucks on fabrication and then you're at the mercy of your fabricator knowing what they're doing...
Funny thing about most of these toe-link kits is that they really only address the inner link end. It doesn't take a whole lot to get the inner link up to sufficient strength. Much of the strength increase from these kits is simply from the replacing the ball joint with a heim joint and using a good quality bolt (the double sheer bar probably isn't even needed with the improve hardware--- provided the bolt stays tight, which is the main problem to begin with)...
Solve one weak link and the problem simply moves to the next weakest link-- being the outer link--- and they break too. Iana did a nice job of addressing the outer link issue without going through the expense of replacing the whole carrier...:up:
Here's a link to his:
http://www.lotustalk.com/forums/f172/new-rear-toe-link-brace-elise-exige-69560/
I think it runs about $5-600USD or so...
Couple pennies for the jar...
Best,
Phil