Has anyone tried one of those tunnit boxes to boost power .Just wondered if they were worth a look at (easy mod) any info would be welcome 
Tune-it??
To me it seems like the usual ‘gofaster’ snake oil. I could be wrong.
I cannot imagine any car manufacturer deliberately holding back a big chunk of economy or performance to then be released by a third-party magic box add-on.
Psssst !! Wanna buy a bridge ?
Just had a quick look. It appears to be like the ‘pedal commander’ and other similar products. As the more recent cars have wire throttle pedal rather than cable, it plugs in line and from what I understand, just ‘improves’ sensitivity of the pedal response. I’ve read that this can be achieved by using your right foot on its own, in a different way?
Barrie
How much ???
You can normally lean the fueling a bit and add a degree or so of advance to gain a bit of power and get better mpg. Manufacturers are cautious to make sure warrantee claims are kept to a minimum. But on an MX5 only expect 5-6bhp more at best.
On turbo charged cars you can make crazy gains some times. My BMW M140 has a claimed 340bhp 3.0 turbo engine but on the rollers they always make 355/360. A remap can give you 430/440bhp. It’s easy with a turbo. The same engine comes in the M3 with 431bhp as standard and BMW do indeed detune it deliberately. Don’t want the M1 being faster than an M3 do we now.
Cheers all think I will give it a miss