Volkswagen's Golf GTD has a loyal following that like loads of low-end power but also enjoy reasonable running costs.

The big question is this: the petrol-powered new Golf GTI is the best hot hatch you can buy - so why would you pay more for a diesel version with less poke?

If you look at Volkswagen's price list, you'll see the entry model GTD starts at €35,740; this is nearly €2,000 dearer than the GTI at €33,820. More importantly for enthusiasts, GTD is down on horsepower with 184hp compared to the GTI's 220hp, although it does have more torque with 380nm (GTI 350nm). GTD is quick with a 0-100km/h time of 7.5 seconds, but it is still a full second slower than the GTI. And while GTD can reach 230kph (manual), the GTI 'top trumps' it again with 246kph.

Where GTD scores well above the GTI is in miserly fuel consumption for a performance car, despite being roughly 30kg heavier. The Euro6 emissions-compliant, four-cylinder diesel GTD can return up to 3.7L/100km - 76mpg in 'old money' - whereas GTI can at best return 5.1L/100k or 55mpg.

Up until the current GTI (seventh-generation), the iconic hot hatch was a fantastic, but expensive proposition. It was never the greenest of machines and attracted high running costs. But now the GTI is far greener. It has dropped a few tax bands, plus it is far more economical to run.

We went to Munich ahead of the GTD's August launch in Ireland to see if the GTD could justify itself.

Physically there are just a few subtle styling differences that mark out a GTD from a GTI, namely a unique GTD grille and bumpers, 'Curitiba' 17-inch standard alloys, twin exhaust pipes to one side, interior monochrome cloth and, of course, GTD badging.

On the twisty mountain roads outside Munich the GTD handled well as it features a lot of identical GTI components (and available options) including the sharp steering rack. The GTD's diesel engine never encourages you to really press on as the GTI's does. The only place where I felt the GTD was really at home was on the autobahn. GTD effortlessly cruised at 200kph and was very refined.

GTD comes in six-speed manual form as standard, but our choice would be the DSG auto gearbox. The engine can make a decent enough, almost five-cylinder-like rumble but, really, we were a little underwhelmed by the whole dynamic experience when comparing it to the stunning VW GTI.

If you do high mileage then the GTD will pay for itself over time in fuel savings, but it still falls short of the GTI for thrilling driving. Another serious consideration is that the almost identical SEAT Leon FR diesel costs about €5,000 less than the GTD.

GTI also has a unique party trick in reserve to make the driving gap even larger. The 'performance pack' option adds 10hp, bigger brakes and, more importantly, a limited slip differential to aid fast cornering, making the GTI even more joyous to drive. Game, set and match to the GTI. VW expects to sell 40 GTDs this year in Ireland and a similar number of GTIs.

Hot hatchbacks are all about feel and invigorating performance. With GTD, buyers have to ask why they should spend more than the price of a GTI - for less fun!

Michael Sheridan