Im(family) traveling toToronto, I ll stay for 2weeks, to enjoy is it better to saty in Downtown or in suburb?

Downtown. Otherwise you'll be wasting a lot of time travelling downtown every day as there is nothing to do in the burbs.

If you have car then suburbs otherwise downtown. Airport and most places are 30 minutes away from downtown.

Avoid rush hours driving downtown.

There is Green P Parking owned by muncipality. Usually costs $15 per day. Weekends, most buildings offer full day parking for $6 or so. When you visit downtown, park in a central location and walk around. Most buildings are connected in downtown.

Staying suburbs will save you some money on restaurants.

There are tons of restaurants where you can eat buffets for 10 bucks or so.

Parking:
http://www.greenp.com/tpa/
http://www.torontosites.info/