With the right tyres, Vortech's can run an upper mid to high 12 (12.6+) and APS TTs might just break into the 11s (usually low 12) with a very experienced driver and high tune
I think stock coupe's are mid to high thirteens aren't they mate?
you wish. I have never seen a UK Z on the strip going below 13.8 (std tyres but Stillen SC) and 13.5 for the Pink Z (albeit drift spec)
US numbers are closer to what you say, but I've never seen them in the UK.
Also 1/4 miles can be affected by many factors, altitude and surface are just 2 of many