Auto Express journalist Owen Mildenhall sets out to find the perfect GT car, and ends up comparing the Mercedes-Benz SLS AMG with Aston Martin’s beautiful new Virage model. The 571 hp SLS accelerates to 60 mph in 3.8 seconds, before going on to a top speed of 197 mph, while the Aston Martin, with a slightly smaller 490 hp 6.0L V12, hits 60 mph in 4.6 and tops out at 186 mph. And doesn’t have gullwing doors…