The Fat Cat bump stops for Spec Miata have always ONLY had one configuration / stiffness. Our Spec Miata bump stops kit use the highest durometer micro-cellular polyurethane that Speedthane makes. A difference in bump stop stiffness can also be identified by weight, if needed, but we don't have a statistical survey of weights at this time. We have never and will never sell anything to an SM racer, SM speed shop, or Mazda Speed Motorsports but the kit which was originally approved by SMAC with any revisions they've later approved (wider spring isolator to resolve rubbing issues). I knew people might attempt to mess with our product (and it turns out I was right via the advanced auto debacle) so I focused on maintaining consistency and uniformity.
The authentic Fat Cat bump stops are molded and precision-cut at the factory which provides similar products for major automakers. Our designated distributor, 5X Racing, receives large bags of cut bump stops and bushings which they package into the official FCM-MT-KIT-SM:
On the topic of identifying marks, on 10/19/17 I spoke with the owner of Speedthane, who said I can have a new mold made with added raised lettering. These could be similar to the 'FCM' currently on the black urethane spring isolator. The Spec Miata bump stop and bushing kit is my proprietary design that I developed with Speedthane's help. They will not sell to anyone I do not designate and I only designated 5X Racing to be primary source. 5X sells direct to Mazda Speed Motorsports and any SM shop or racer who wants to buy direct. I have not heard of any major supply / delivery issues in the past few years.
I have asked Todd Lamb in another thread here (post awaiting moderation) if markings are required, which I'm prepared to do on the bump stops. It would take 2 months to have the new mold made and a few weeks to get several hundred units produced. Phasing in would be up to the SMAC. It may take a few months but with a visual guide as already exists the new molded parts would give added confidence. This will resolve any questions about identifying the parts, along with a basic visual inspection. The manufacturing process would be the same, only with the new parts being marked and samples provided to SCCA Tech Dept. for their compliance kit.
In terms of quality and complexity, these MCU bump stops and bushings are created through a precise and proprietary process. You can't just pop them off in an oven in your garage. They're not urethane like rubber boot soles but micro-cellular polyurethane. Our supply process has worked, long ago we addressed the problems that arose from the original AWR kit.
I'm glad non-compliant kits have been called out so we can guarantee quality and consistency by enforcing use of only Fat Cat parts as one of two SMAC-approved kits (and the superior kit at that). I'm happy to invest in a new mold to simplify future enforcement.