Hi Janry1!

The vios is a nice little car indeed! Fuel efficient, and with just a few simple modifications, you can really change the whole look of the car.

I also own a Vios Gen2 and Ive done quite a few modifications on it myself, but it still looks clean and simple. Overdoing it will make it look ricey indeed. The key is modifying in the right places, a little touch here and there, but not overly done.

Let me help you a little bit.

HID - HIDs are nice, only drawback is that they are made for projector use. Putting them in halogen housings like the stock vios lamp would just scatter the light, and you wont get proper lighting output, which can potentially be more dangerous to you, and oncoming cars. Unfortunately no projector headlamps exist for the Vios, you only choice is to retrofit projectors into the headlights, I have to warn you though, this can be expensive and run you about 25k-30k for a full conversion complete with HIDs.

I can recommend Wurth Halogen bulbs, its a little prices, in the 3k range for halogens but they are worth every peso, very clear output even through rain.

If you are still hell bent on using HID, make sure that you have the umbrella cap on, so you wont blind on coming traffic

I have to admit im using HID now, and I regret replacing my Wurth Bulbs, good thing I kept the umbrellas on, so im the only one inconvenieced hehehe.

As for Visors, personally I'm really not into them. Aesthetically I think the vios looks better without them. You can find them in Toyota and some Car Accessory shops.

Chrome - honestly I love chrome, but here's the thing.. chrome can be easily abused and if so will make your car look cheap if not used in the right places.

Avoid putting chrome trims on your headlights, tail lamps and cheeklights. The best way to gauge where to put chrome trims is to take a look at high-end cars like a Camry, Accord, and even higher end cars like benz and BMW and study where they have chrome trims on. Usually you would find them on the grill, door handles, sidemirrors, trunk lid, windows etc.. just base it on that and you might even put a little more touch of class to your Vios.

Mag wheels. There are lots of designs to choose from. The size is really up to you and your driving habits. 16s for me are too small for 2nd Gen, but they provide you with a very comfortable ride. You can still achieve this with 17s and filling up with nitro on your tires and using a 45series tire.

Your choice of mags again depend on your taste, you can go for classic designs, or more modern designs. I personally like mags with a polished face, and black trims which is more contemporary nowadays. Mesh Types usually give you a Euro sort of feel, and Spoke types gives a more JDM feel, Chrome is more DUB, and Deepdish, polished rims are more VIP Style. Go with whatever you think looks best on your ride.

Try MCS tires on Pasay road look for Mang Mario, very nice guy... they have a fairly decent amount of mag wheels to choose from. Madali pang kausap si Mang Mar.

Personally I'm using 18s, its a bit impractical coz you really have to be mindful of the road, but it sure gives you happiness every time you look at your car
Kanya kanya naman yan, so gauge your preferences and make sure you know what you want, porma vs ride quality.

Spoiler - This looks nice also on a vios, you have 2 choices the OEM S type and TRD. The oem spoiler looks nice and sleek, while the TRD one has a more aggressive look. You can check Clifford Bodykits alam ko meron sila parehas nun. I got mine from clifford for 6k with paint and installation na yun.

Muffler cutter dami jan. Try muffler land on Tomas Morato, they have lots to choose from, better than off the rack bolt ons...

Neons - DONT hehehe. Neons are probably only good if you are entering your car in a car show. Neons only attract attention, mostly with MMDA haha, baka hulihin ka pa. And also, medyo Ricey ang dating nyan so AVOID!

Check out my car domain page, you'll see some mods Ive been doing ever since I got the my Vios, just to give you an idea of what you can achieve with your Vios with a few modifications.
http://www.cardomain.com/ride/3179625

If you need any more help on modifications, I have a blog specially catered to VIOS modifications.
http://www.viosunderground.com

You may also want to check out Vios Club Philippines
http://www.viosclubphil.com

The vios is nice car... I love it! Good luck on your modifications!