BMW Z4 news - V10 rifle - 2009

Seems it's a good day for wedging massive V10s into small vehicles.

OK, this isn't quite as loony as that Viper-engined motorbike, but it's gently unhinged nonetheless.

German tuner Manhart - and we are far too grown-up to make a joke about that name - has wedged a 5.0-litre, 550bhp BMW-sourced V10 into the BMW Z4.

So that's 550bhp in a roadster weighing just 1,450kg - a power-to-weight ratio of 379bhp per tonne, more than the Ferrari Scuderia.

Manhart says the mad Z4 will hit 62mph in 3.9 seconds and, thanks to a sneaky removal of the 155mph limiter, run close to 200mph.

If, however, you fancy a slightly more retro flavour to your V10-powered roadster, how about the Weismann MF5 set to debut in Frankfurt in a couple of weeks?