Each first entry into istanbulinhours.com still has a pop-over window advertising that a new tour option will be added as of 10.08.2015. There was earlier discussion whether that meant "October 8" vs. "10 August" but we are way beyond both of those at this point. The schedule does list it, with same sites each day of the week.

Has anyone tried this new option?
Any feedback whether it is worth it to leave the airport and come back in, all for a 2.5 hour tour??

We have qualifying layovers in both directions, and will be in business on all segments:
On the outbound, the layover is 9:10, but not arriving until 15:55. Will probably just stay in the lounge.
On the return, the layover is 8:10, arriving at 05:30 and departing at 13:40. That seems about right for the morning tour, while still providing time in the lounge.

Thanks for any insight!