Sorry it's sold.
I have an RX-8 front sway-bar from an 04 to 08 color coded yellow. It would come with new polly bushings to fit in your stock MX-5 brackets. I sold the rear sway-bar that mats with this front bar. So you would need to buy an RX-8 R3 rear sway-bar. The R3 sway-bar is not hollow, it's a solid steel. You can buy the RX-8 R3 sway-bar from any Mazda dealer. I bought the one I sold from Jason @ Montgomery Mazda for about $74 plus a $8 flat shipping rate. As for polly bushings you would need to order Eibach bushings part number 5536-312 HK. You can buy from any one who sells Eibach parts. This would included Goodwin Racing, Tire Rack or even Summit. Make me a fair offer and it's yours. I just need to find a box and it will be ready to ship.
My direct email is; email@example.com