Nice calculation... But needs some corrections.... The one u r calculating is not power to weight ratio, it is weight to engine volume. The value that tells us about vehicles performance is weight to power ratio. So in your calculations you calculated the laden weight of the vehicles correctly but used cc instead of engine power to divide the weight.
For BRV: 1730Kgs/88kiloWatts = 19.66 Kgs/kiloWatts
For Gli: 1650Kgs/84kiloWatts = 19.64 Kgs/kiloWatts
So the Gli marginally wins by 0.02 cuz in weight to power ratio, lower one is the winner.... But one must also consider that BRV carries load of 7 ppl... So BRV is at advantage here in loading capacity