1. where is a good place to buy? (either online or locally in TORONTO to YORK REGION area)
try ddmtuning or motorfiend ,they are both good sites for hidkits
2. what is a good brand for the is250, that won't cause any problems later on and is reliable?
You can get OEM hidkits now they usually have 18monthes guarnatee
3. what do i exactly have to buy? (full conversion kit? bulb? ballast? i'm new at this....)
You need to buy full hid kits
4. what is a reasonable price for everything? (low beam + fog together)
around 70$,you can get them all
Hope it helps ya