I went on my Suzuki Cultus Limited Edition, from Larkana to Khunjerab Pass via Babusar Top, this means yes WagonR can go as well, before leaving make sure to get your vehicle inspected from Suzuki Authorized Dealer as it will allow you to drive worry-free. Please also note that Basar Top remains closed till mid of June, so better to go in the end of June or later, I went in first week of October 2017 while we reached there on Babusar Top, the first snowfall of the season just started but it was very little which did not created any problem, we crossed Babusar top again after 4 days and it was freezing temperature, but no issue for travel/drive. We were five. you can see our videos here: https://www.youtube.com/watch?v=B8NSyplDfck