An aftermarket part isn't neccessarily a rip-off. If RB spent their own R&D dollars to create a header that bolts into a Mazda, which is NOT a duplication of a factory part, it is a design belonging to them. Therefore they could and likely would sue you if you copied their design and manufactured it for distribution.

 

I wasn't paying attention at the time; did Mazda seem to mind when RB stole their header design?

 

Is the RB design identical to the Mazda design? If it is, do we know that RB didn't license the design from Mazda, or even design it for Mazda as a parts supplier in the first place (as they do now for Protégé components)?

Are you willing to risk being hauled into court and found guilty of parts counterfeiting to find out?

 

It wouldnt be counterfeiting, its not like we would put RB's logo on and try to sell it..
Plus, Its not like RB can do anything if we take their basic shape and change the dimensions slightly

 

Heck, it'll be more than slight changes if we want more than slight power gains over RB.

And I'm not worried because this project will probably never get off the daydreaming stage.

 

Well, there are only so many ways you can make a pipe from point A to B, but reverse engineering something is still theft of intellectual property. It shouldn't be too difficult to make your own measurements.

I think that if I were to spend the money on a RB, then I would also spend the money on a coating like these guys offer:
Performance Coatings "Cermachrome"

Probably cost around $150, and it should make it last really long, without rusting. BTW, I've heard nothing but good things about this shop from people building high performance motorcycle engines.