Mountune launches new MR500 Focus RS Track Pack

The old RS was a giggle with 350hp - now it has another 150hp

By Matt Bird / Monday, 11 August 2025 / Loading comments

Old fast Fords never die, they just get faster, or so the sticker goes. With Ford having cancelled another Focus RS (indeed it seems reluctant to pursue anything very interesting right now, but that’s a discussion for another time), the Mk3 will forever remain the final iteration. Quite some car it was, too, with 350hp, a Drift Mode and a host of trick bits.

It didn’t take long for the aftermarket to optimise it further; you might remember the FPM375 upgrade from Mountune that liberated 375hp and 376lb ft for a few RS special editions. That development hasn’t stopped with the car out of production, either - 400hp was soon available from the Essex-based tuners. Now Mountune has launched its most potent product yet for the Mk3 Focus RS: the MR500. And who wouldn’t be interested in a 500hp, four-wheel drive fast Ford?

There’s a small caveat to get out of the way first, as Mountune only offers this upgrade to those who already have its M400X pack. That lays the foundations for big power, with forged pistons and better conrods alongside the usual turbo power goodies: high-flow induction, uprated intercooler, freer-flowing exhaust and so on. MR500 builds on M400X with a new Mountune-configured BorgWarner EFR-7163 turbo plus a raft of new hoses, clamps and gaskets, uprated cams and valves, a burlier downpipe, colder spark plugs and a fuel pump to handle the increased appetite for super unleaded, alongside all the other odds and sods associated with going to a giant turbo. If you were looking for mention of a Turbosmart EFR B1 series single port actuator or Ni-resist cast turbo adapter assembly, here they are.

Alongside the headline power figure, Mountune claims 516lb ft of torque for the MR500 - a huge uplift from the standard car’s 347. So this is going to be as fast as hell, if not a bit more so. It also comes with functionality seen on previous Mountune builds, including no lift gear changes and full-time launch control (i.e. it doesn’t have to be activated). ‘As proven in multiple mountune Racing engine applications, the mr500 will transform your driving experience!’ We don’t doubt that for a second…

The MR500 upgrade is available now, priced at £11,495 including the VAT - Mountune has to fit it, too. Those beginning from a standard car will have to factor in things like the forged Mahle pistons (£949), forged conrods (£1,450), upgraded intercooler (£795) and the £699 mTune handset, before embarking on the journey to 500hp, so it’s going to be a significant investment whichever way the project is is approached. Particularly with even higher mileage Mk3 Focus RSes continuing to command £20k; still, nobody knows fast Fords quite like Mountune, and the prospect of 500hp in a Focus RS is hard to ignore. We’ll let you know the reality as soon as we can bet behind the wheel.