What's all this about?

We've got a Volvo XC90 Polestar on our hands.

What?! Seriously? That's the next performance model, is it?

Yes. Well... sort of. Actually, the XC90 D5 diesel and T6 petrol models have been given a mild remap by the Swedish racing outfit that gave us the superb V60 Polestar. The software upgrade, called Polestar Performance Optimisation (PPO), improves throttle response, speeds up the gearbox shift patterns (and also prevents it from changing cogs mid-bend, for better stability) and adds more power and torque.

Ah, now we're talking! And what sort of gains are we looking at?

Umm... you might not want to get your hopes up too much. The 225hp/470Nm D5 gains 8hp and 30Nm, for figures of 233hp and 500Nm; while the T6, standing at 320hp and 400Nm as standard, climbs 14hp/40Nm to 334hp and 440Nm. No word on precisely what these do for the on-paper stats, but expect mildly improved standing start and in-gear acceleration, as well as modestly greener consumption and emissions data; Volvo says the mpg/CO₂ emissions are unaffected, but added mid-range torque means the engine is working slightly less hard in day-to-day driving.

And the cost of these remaps?

They retail at £835, including VAT and fitting, the latter of which takes just 30 minutes at any authorised Volvo dealer. Obviously, this work does not affect your Volvo warranty or the scheduled service intervals. Nick Connor, Volvo Car's UK MD, said: "These new Polestar Performance Optimisations make our cars and Drive-E engines even more dynamic and desirable. The combination of increased power and torque - especially at medium revs - and the changes to make the entire drivetrain more responsive ensure that owners will really feel the difference these optimisations make."

Are there any more PPO upgrades?

Yes, you can have the PPO on the 190hp/400Nm D4 diesel (up 10hp and 40Nm, to 200hp/440Nm) or the 245hp/350Nm T5 petrol (up 8hp and 50Nm, to 253hp/400Nm). The D4 upgrades are available for the V40, V40 Cross Country (CC), S60, V60 and XC60; the T5 enhancements are only offered for the V40 and V40 CC.

Can you have it fitted to older Volvos?

Apparently so. Until the end of December, any 2005MY to 2015MY all-wheel drive Volvo can have the PPO fitted at a cost of £620, saving £215. Volvo doesn't provide horsepower and torque gains data for these models.