The Ford Focus ST and Fiesta ST are now available with performance-enhancing Mountune power upgrades.

Developed by tuning specialists Mountune, the Focus ST package boosts power output from 250PS to 275PS, cutting half a second from the 0-62mph time to less than six seconds.

Torque receives a boost, too, climbing from 360Nm to 400Nm, leading to a corresponding improvement in in-gear acceleration times: 31-62mph in fourth gear is now nearly a second faster at 4.9 seconds.

The upgrade includes revised ECU mapping, a high-flow air filter, cast alloy inlet duct and larger intercooler, both in a choice of silver or black.

The Fiesta ST Mountune package, which consists of a remodelled airbox with secondary inlet, high-flow air filter and revised ECU mapping, increases power to 215PS (on overboost), dropping the 0-62mph time from 6.9 seconds to 6.7.  Maximum torque increases from 290Nm to 320Nm, dropping the 31-62mph fourth-gear time by 0.7 seconds to 5.7.

The upgrades can be fitted at one of 120 Mountune-appointed Ford dealers, with the work completed in less than 60 minutes for the Fiesta ST, and less than 90 minutes for the Focus ST.

The Focus ST Mountune package costs £1,225 for silver and £1,275 for black, while the Fiesta ST Mountune package costs £599.  Both packages maintain the existing factory warranty.

“We worked hand-in-hand with Ford engineers to deliver what we believe is the best bang-for-buck value on the market,” said David Moore, Mountune marketing manager.