http://www.flyinmiata.com/dealoftheday/Flyin' Miata said:
FM frame rail reinforcement kit
Your Miata is sad. It's all floppy. And nobody likes being floppy.
That's why Flyin' Miata - the Pfizer of the Miata aftermarket - came up with a frame rail reinforcement kit. Suddenly, old Miatas found they had a new vigor. Most were stiffer than they had ever been! Stiff is good.
However, time marches on. The design of the original frame rails was tweaked with sexy cutouts and cool laser engraving. These original frame rails sat on the shelf, unloved and ignored despite their shiny stainless steel good looks. But they can still make your Miata young again! And the best part is that they're $90 cheaper than the new ones.
Fits any Miata, although cars with the 2001+ Sport bracing will either have to lose one cross brace or a little bit of modification will have to be made to the frame rails. Because these were made before the butterfly brace, the holes may not line up perfectly with that upgrade. No hardware included, 16 nuts and bolts required to install.
$100 bucks on old school FM frame rails! I'd get that in a heartbeat if I had the extra money to spend.
One of you damn ClubRoadster guys better get it! If you want it CALL right in the morning!