Not that I doubt your research and investigation into tyres but you really shouldn't be basing tyre choice on how it compares to real life laptimes. There are many, many factors at play in a videogame making such a comparison pointless. Just because you can lap at a similar time to real life doesn't necessarily mean you've got the 'right' tyres on. Unless both the car and track are 100% perfectly simulated there are other factors at play in laptime. Whose to say you didn't go faster at Tsukuba just because the virtual tarmac was grippier than the real tarmac for example?
Now if you're also comparing based on G and individual corner speed I take that back but to compare solely on laptime is not wise.
I know what you mean, the tires that I mentioned in all my replica tune are only guidelines, most of them needs somewhere in the middle, for example, the Ferrari F40 with comfort soft, it's faster easily by a second - so it needs somewhere between comfort medium and comfort soft, fitting sports hard will be much to grippy overall and will result in lap time quicker by over 2 seconds even with moderate pace - no even real life BM video pace. Now, anyone can say I'm wrong, but imagine how much wrong would it be to say sports hard it the right tire to compare with real life factory tire ?
When there's a video of real life lap, I also compared the video with my replay, how the car hit the apex, how quick the cornering speed and the elapsed time on each hairpin at Tsukuba for example. When I drive to compare the lap time, I don't drive like most TT driver, I drive as smooth as a real driver would, avoid slides, hit the apex in the same manner.
Now most of the tire I used ( comfort ) always still quicker than real life ( usually by a few tenths to a second ), I know the reasons, which is why I tried my best to get close as possible for the car, from power, weight, handling characteristics, gearing, and top speed. I also try to find top speed of the car on each braking point and replicate that as well. I don't tune replicas to lap as quick or as safe and easy as possible for TT drivers, I make them drive like they would in real life, if the real car is hard to correct when oversteered, then it will be in GT6. Sometimes I even use camber to reduce the tire grip to get closer to the cornering speed and overall lap time. This happens when I have CS tire, but if I go down to CM, the lap time gets slower than the target time even on maximum pace. So I use CS and use some camber to balance grip, this is a good use of PD broken camber
I limit the camber to real life alignment level allowed by the suspension. Let's not get started with LSD, I tuned LSD to replicate real life LSD behavior, so you'll find my replica LSD will be different than most tuner here who wanted easy and safe to drive LSD, which mostly have values close to open differential ( when initial, accel and brake are below 10 )
And my method is still better than people who just stick some sports tire and say this is as good as it gets for comparing to real life car.
Whose to say you didn't go faster at Tsukuba just because the virtual tarmac was grippier than the real tarmac for example?
You just need to drive some of my Best Motoring replicas to see how close they are to real life laps when driven like in real life in game.
This is getting OT
Feel free to take it on my garage or PM
Is the stig still Tiff Needell?
Buckets of oversteer in that GT-R. It doesn't normally handle that way in GT6.
Not sure about the Stig, but if you want that oversteer handling, fit comfort soft or below, you'll get plenty when the GTR pushed hard in mid corner
. Being an Aussie , Bathurst is my favourite track. 
