28 is pretty high for et streets. Drop em to like 20 and see how you go. That mph seems a little low as well for 315rwkw (well comparing to mine anyway), I went last week and it was quite humid and I was hitting about 186kmh/115mph and 12.2-12.4 with 1.8 to 1.9s 60 footers
Are you manual shifting as well?
Best I've done with this power is 11.87 on a nice cold winters night so hopefully you'll be able to hit something like that with practise if it's cold.