The pick is the turbocharged 1.6 petrol with 178bhp. It stops just shy of feeling like a hot hatch, but the performance is still impressively strong and responsive. Two 1.4 turbos are also available, but they're a bit weak for a car with such sporting pretensions and it’s the same story with the 1.7-litre diesel, although it is the most economical choice. The 2.0-litre diesel pulls strongly from low revs, so it's easy to build speed quickly.
The GTC is considerably sharper to drive than the standard Astra. It turns in quicker and carries a good bit more speed through a set of bends. Body lean is also well suppressed, but the steering could do with more feel. As a result, many rival cars are more fun. The ride is firmer than the standard car's, but it's comfortable enough - provided you stick with the standard 18-inch alloys.
We like the sound of the 1.6 engine - it gives a throaty rasp when you thrash it, and stays subdued when you don’t. The 1.4s aren't so good, though, sounding decidedly boomy when you rev them. Both diesel engines are a bit clattery, too, and it's worth noting that the bigger the wheels you choose, the more road noise there is.
The GTC is cheaper to buy than the equivalent VW Scirocco, and you’ll probably get a bigger discount, too. However, the Astra will lose more cash in depreciation, so you’ll need to barter hard to make the GTC affordable long-term. Fuel economy and emissions are competitive.
The GTC's cabin has some wow-factor, but once you start poking at the plastics, you'll realise that they aren't quite as sumptuous as they first appear. The cabin still looks smart, though, and the slick switches help elevate the feeling of quality. Vauxhall has a poor record in our reliability and JD Power customer satisfaction surveys.
The GTC has all the same safety kit as the hatchback, which means all versions to have six airbags and stability control. The security measures are similar, too, meaning an engine immobiliser and deadlocks are provided as standard.
Unsurprisingly, the dash looks very similar to the normal Astra’s. That means it’s somewhat overloaded with buttons, so using the various functions can be quite confusing. You don’t get as good a view out of the back of the GTC as you do out of the hatchback, though, because it has a much smaller rear window.
You get bags of head- and legroom up front, and enough space for a brace of burly adults to sit in reasonable comfort in the back: it’s a little more hemmed-in than in the hatchback, but better than in most coupe rivals. Shoulder room is too tight to regularly carry three across the rear bench, but at least you get a generous 370-litre boot.
There are two trims to choose from. Sport cars come with alloys, air-conditioning, and a DAB radio, which is all most people will need. SRi cars, meanwhile, add xenon headlamps and automatic lights and wipers.
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This is our favourite Vauxhall Astra GTC. The 1.6T is well worth the extra over the smaller petrol engines, and Sport trim has enough equipment to satisfy most buyers.