Small and low powered car like Vios better just stay with 15' rims, or at max just 16'. 17' is way too big, makes the car slow and very uncomfortable due to having to use wafer thin profile tires. Best is use 15x7jj rims with 195/55/15 tires coz you still keep weight down while improving handling by using better tires (coz that size has many choices of good high performance tires).

Well the weight is actually not just detrimental to acceleration but also how hard the suspension needs to work to control that unsprung weight. And then there's fuel consumption and braking distance which also get affected negatively. Note also going too thin on tires might not always be beneficial to handling because such wafer thin tires means very stiff sidewall hence very less flexing to absorb road irregularities. So instead of gripping, the tires may actually skip and hop over the bumps and therefore loosing traction! Then there's also wet driving, which normally will require softer setup, so if you go with very stiff thin profile tires then your car will feel more nervous in the wet. All of this are not subjective but physics. Then there's of course like I mentioned above, the uncomfortable harsh ride but I guess that's kinda subjective.

So you need to strike a good balance, not go overboard with big size rims. You'd want a good improvement in handling while still able to handle most of the road irregularities and wet condition, all of which we often experience in Malaysia. The main key with improving handling is not all about going as big of rims and as thin profile tires as possible but also more about balance and what type of tires you use. I just bought a Swift Sport that came with 17' Lenso with just normal Toyo DRB tires and I honestly hate the rims/tires setup due to all those reasons above! Within 2 weeks I changed to 15x7 rims with 195/55/15 Hankook V12E2 tires and I can tell you its the biggest improvement I made to the car handling, not to mention all those other stuff I mentioned above!

That's why I suggest the best is just 15' rims with 195/55/15 tires where you got options of high performance tires at still relatively cheap price, tires thin enough to give good feedback and handling but still thick enough to absorb irregularities better and still comfortable. The rims also will be much lighter still. If you want a bit more aggressive and better looking then opt for 16' rims BUT it's much less choices of good high performance tires available AND the prices are much more expensive too (almost double the 15' options).

This post has been edited by 6UE5T: Oct 21 2018, 12:35 AM

It will make a noticeable difference even just going from 14 to 15 because you already reduce the tire sidewall height by 1.1-1.3cm! With 195/55 tires, you have sidewall height of 10.7cm which is in the balanced range for handling performance yet flexible enough to be comfortable and grip better for not so smooth roads (for me personally the ideal range of sidewall height is between 10-11cm. Going under 10cm will start making it a bit stiff while going over 11cm will have a bit too much flexing). If you use 17' but try using thicker profile then it will get out of tolerance for your overall diameter and give even more negative effect: risk of scrubbing to the body, even worse acceleration, fuel consumption, and braking because on top of extra weight (bigger tires is heavier) you also add extra overall diameter. You need to maintain no more than 3% difference to your stock overall tire diameter.

He said it's 14' rims so the tire size should be either 175/65/14, or 185/65/14.

If the most economical way then just change to some good sport springs which are still relatively comfortable paired with still stock shocks. If want better then also change with sportier shocks. If want the best then use adjustables/coil overs but you need to play around with the setups until you find the most suitable setup for you but it won't be cheap/economical.

The spring price is cheap but the installation is expensive! Anyway if you buy import branded springs like Eibach/Tanabe/Tein/RSR, they'd easily cost 1k or more just for the goods not including installation labor.