Well as I said, I can't speak from personal experience. What I do know however is that full fat 997 gt3 cup race cars will do a 1min 9 sec lap with a good peddler. Given the extra weight, lack of race set up, road tyres etc, etc the road version will be significantly slower (I accept that the 991 will be quicker than the 997). However, a 1min 12 sec lap is a fairly quick time even for a race car with decent P/w ratio. Hence my thoughts was simply that road gt3 would likely be a good couple of secs slower so say 1.14 & there's your 5 sec difference with the LT. Not scientific at all I know! I would be interested if you have any actual figures to share.Around Silverstone International? 5-6 seconds? You must be joking as I can't believe anyone actually seriously thinks that.