© Copyright by Boss Frog Inc.  All Rights Reserved.

Automotive Rollbars and Aftermarket Products for Miatas and MGBs

Miata Performance

If you have ever jacked the car up on the frame rails, then you know how easily they bend and deform.  These steel rails slip right over (under) the stock frame rails and bolt into place through the floor to provide additional stiffness where it counts.  We have added lightening holes on the bottom surface but the sides (where you need it) are full strength.  Kit includes 3/8” grade 8 hardware and requires drilling of 20 holes through the floor.  Fits ’90 – ’05 Miatas, but sport bracing may need to be modified to fit.


Miata Frog Rails (Frame Rails)


Shipping & Handling $25

Frog Rails (Frame Rails)

An unrestricted aluminized pipe is coupled with two heavy duty flanges that bolt right up to your exhaust in place of the stock cat. Includes gaskets and mounting hardware.

Frog Arms

What the heck are Frog Arms?  They are braces that get installed underneath the front fender of the Miata.  They bolt directly to the door frame hinges, and through a small port in the fender, near the shock towers.  The Frog Arms stiffen the unibody both vertically and laterally, and eliminate some of the rattles and shakes common with Miatas.

What do they do?  People who have installed these braces have noticed a significant change in the front end performance. For road tracks, they report the change as similar to adding a front sway bar.  For drifting, they report more stable handling with less bump steering.  For everyday street driving, people report less shakes and rattles going over potholes and railroad tracks.

Note that the Frog Arms make the front end considerably more stiff, thus they will increase the driving feedback.  This will NOT smooth out the ride of the car.  The front sway bars will work much more effectively, and the handling around tight corners will be noticeably changed with the reduce body flex.  Frog Arms are powdercoated green.  See the mounting instructions here.


Miata Frog Arms

Shipping & Handling $25

Straight Cat

The Boss Frog "Straight Cat" is a great alternative to knocking the center out of your stock catalytic converter, or buying an expensive high-flow model.  If you are still using your stock (or slightly modified) catalytic converter, consider the Straight Cat .  
If you have an aftermarket exhaust, the Straight Cat will take some of the "rattle" out of the sound, bringing out more of the growl sound that you paid for.





2" Diameter Straight Cat - for '90-'93 Miatas

2-1/2" Diameter Straight Cat - for '90-'93 Miata

2" Diameter Straight Cat - for '94-'97 Miatas

2-1/2" Diameter Straight Cat - for '94-'97 Miatas




Shipping & Handling $25

Frog Ribs (Door Bars)

Door Bars are used to stiffen the chassis in the weakest part of the car – the door.   Traditional single-tube door bars with two mounting points do little to stiffen the frame  The Frog Ribs are mounted in four places – the rear bulkhead, the seatbelt mount, and the floor in the center and front – so they provide a noticeable change.  These door bars are made using smaller diameter 1” tubing so that they fit better in the tight space between the door and the seat.  They are built to retain vertical strength by using a unique I-beam construction with plates spanning the tubing, while allowing full access to the seat controls and dead man pedal.  These really do help to stiffen the frame, and will change the driving feel. See the mounting instructions here.


Miata Frog Ribs (Door Bars)


lose the tail, grow some legs

Shipping & Handling $12

We now offer 2 sizes of tubing for these Cats - a 2" tube with smaller flanges for stock exhausts or a 2-1/2" tube for racing or modified exhausts.