My 156 Selespeed egine has picked up an problem an bent all the valves. We don't know wat the cause is except that it could have been an over-rev, something that alfa says is not possible with the selespeed.
The Data that has been taken from the cars computer says that the max rev that the engine has done is 7320rpm, is this higher that the rev limit of the car.
Rev limiting is done by the ECU, but Selespeed changes up before the limit is reached (unless you're in top gear doing 154mph!).
Some people blame Selespeed for everything, (including bad weather!), but I don't think it would cause over-revving.