Several car salesman told me: “Next year price will go up! Buy NOW!”

Well done. All the fear mongering will actually lead to a COE plunge. There was a run up prior to the end of this year because of all the panic buying, then it will stop as people adopt a wait-and-see attitude. By then, the car salespeople will tell you that COE is low, and it is the best time to buy. No matter COE high or low, they will spin a story to sell their cars.

My guess is that sometime in Q1’18 will be the best time to renew COE, where it should plunge back to $40K or even $30K+ levels (for Category A).

Yes, the new Euro 6 CEVS will affect car prices, but the market will adapt. It’s not like this is the first time the Government has introduced changes to CEVS or COE (e.g. the horsepower categorisation). Eventually the whole system will net itself to zero, i.e. COE drops + CEVS goes up. Car prices will probably just remain the same, and for a while until manufactures catch up with Euro 6, then the regulations will likely change again when majority of vehicles qualify for CEVS discounts.