Was wondering if any Viva 660/850 or Viva 1000 non-premium who is going to upgrade their tyres/wheels and want to get rid of the old tyres? Drop me a buzz. Thanks

Nah... the proper upsizing should be the following

13" either 155/65R13 or 165/60R13

14" either 165/55R14 or 165/60R14

But the one with the most tyre choice would be 165/55R14, from normal tyres to performance tyres also have a lot of options for 165/55R14

Shouldn't be too hard getting 14" wheels also, even stock Wira/Satria/Putra and Toyota Vios wheels can be used.

Am not too sure how's the FC like when using 14" though, definitely it'll increase due to the increased weight of the 14" tyres, and how much more it'll increase would depend on the choice of wheels you choose for the 14" rim, whether it's light or heavy.