tbh the shafts are just fine on the road... They dont tend to fail, even with big power... However they have been known to fail on santapod with hard launches.... Which is understandable... The gearboxes are ok too tbh... If anything is going to fail it will be the 3rd gear... Anything over 300bhp and there just timebombs... There is speculation that the older style GT Turbo gearbox's are stronger then the Glanza ones. But it may just be because the 3rd gear ratio is longer in the GT.... Who Knows... Hope this helps!