New mod or possibly old
 

Actually saw this on ebay and kinda made since but I did it at home and instead of waste money on theirs...

I haven't seen anything about it on here but here goes nothing

Its a throttle body coolant bypass

pretty easy to do with some vac caps and a vac connector.

HP gains probably not although ebay claims 8Hp *cough* bs

Quicker throttle response yes.

Logic: keeps hot coolant out of the the throttle body heating up the air going in.

I don't know how Mazda does it, buy many of the companies that use "coolant" to "heat" the throttle body do so only when OAT is below 40°F. The thing is, by heating the throttle body you bring up the temperature of the intake charge, and that helps fuel atomization, which in turn helps fuel economy. In theory at least, during the warmer months, coolant never makes it anywhere near the throttle body.

ef it, waste of time or not, 5 min, not a big deal to me