If you plan on spending thousands of dollars (or already have) on modding your vehicle, you also want to make sure that your mods won't void your warranty. But even if your warranty is not an issue, the law might be. So do some research before you get those new rims and tires, lower your suspension, or upgrade the air intake system.

To get you started, we've put together this list of the most common mods people make to their stock vehicles and weather they're considered legal in Ontario, Canada.

Common Exterior Mods

Tinting the Windows: If you want to tint your rear windows you can do so in whatever colour of intensity you want. That's given your vehicle has side mirrors which provide a clear view if the rear. What about the front windows? You probably shouldn't touch them if you want to stay within the law. You are required to have a clear view out of your front windows and windshield. And a police officer needs to have a clear view in.

Changing the Gas Cap: Your gas cap's seal needs to meet certain emission standards. Put simply, all of your vehicle's stock emission control equipment should stay the way it is.

Lowering the Suspension: Go ahead. But keep in mind that your tires should not be coming into contact with your vehicle. Your front wheels need to be visibly aligned. And no part of your vehicle can touch the ground.

Oversizing Tires: That's allowed, as long as your new tires have been approved for highway use. You might be required to also install mud guards or flaps on oversize tires. And again, your tires should not be coming into contact with your vehicle.

Changing the Paint Colour: That's not a problem at all, as long as you apply for a new vehicle permit within the legal time frame. The same rule applies to changing your engine, fuel system, doors, axles, or chancing the vehicle body style.

Adding Green Side Marker Lights: To do this, your vehicle needs to be longer than 6.1 meters. The lights cannot be visible from the front of the vehicle, or the rear of the vehicle. And they should not be flashing.

Adding Coloured Lights or Turn Signals: The only legal colours for the front of your vehicle are white and amber. Keep in mind that red lights are restricted to police cars, fire trucks and ambulances, green is restricted to Volunteer Firefighters, and blue is restricted to snow plows.

Installing Racing or Drag Slicks: The law requires you to drive with tires that are marked for highway use and are DOT approved.

Adding Graphics to the Top of the Windshield: This may or may not be illegal. Size is key - you should not have anything obstructing your view of the road. Try to avoid the area that's swept by the windshield wipers.

Replacing the Windshield and Door Glass: If you're looking to get rid of some body weight, you might look to replace the heavy windshield and other glass. Keep in mind that installing non-safety glass is illegal.

Removing the Wipers or Replacing With 1-Blade: You're required to have a system for removing moisture from your vehicle's windshield. You can replace your wipers with a one blade wiper as long as it doesn't obstruct your view of the road and keeps the windshield clean.

Installing Smoked Headlight Covers or Masks: It's against the law to cover your headlights with tinted or coloured materials.

Adding a Tail, Fin, or Spoiler: That's perfectly legal. The only thing you need to worry about is securing it safely to your vehicle, and keeping it out of the way of your mirrors.

Installing a Nitrous Oxide System: It's legal to possess nitrous oxide. But... there are a ton of rules around it. To begin with, the system needs to be mounted securely. The bottle of nitrous should be mounted securely as well inside the mounting brackets, and kept away from crumple zones. If you have a hatchback, your vehicle needs to have a blow-by tube routed underneath. And you're not allowed to remove the bottle's date of manufacture.

Installing Neon Lights Around the Licence Plate: It's actually illegal to have any light other than white on your licence plate. And the light needs to be directed at the licence plate alone.

Upgrading the Exhaust System: You can do this. But it is illegal to install a muffler cut-out, straight exhaust system, gutted muffler, Hollywood muffler, or by-pass.

Adding White, Blue, or Green Turn Signals: It's illegal to have white lights in the rear (excluding the reversing lights and the licence plate light). Green lights are restricted to volunteer firefighters and blue lights are restricted to snow plows.

Common Engine Mods

Disconnecting the Oxygen Sensor or Charcoal Canister: Like with any other Emission Control Equipment manufactured on the vehicle, the oxygen sensor and the charcoal canister cannot be removed legally.

Installing a Breather Filter or Cold Air Intake: Emission Control Equipment manufactured on the vehicle needs to stay in place and operate as intended. That being said, you can make changes to the positive crankcase system as long as it remains a closed loop system and all emissions are routed to be burned off by the engine's combustion components.

Common Interior Mods

Replacing the Instrument Cluster or Steering Wheel: You can make these changes to your vehicle's interior. But make sure that your odometer works as it should, and if you're installing an aftermarket steering wheel, keep your horn switch.

Replacing the Seats or Install Racing Harness: There are no restrictions on replacing your seats, except that they cannot be marked as "not for highway use". Replacing your seatbelts with a racing harness is also allowed. But again, the racing harness cannot be marked as "not for highway use". If you're going to do this, check that your their anchor points are strong enough.

Installing a DVD Player or TV on the Dash: This is probably illegal. You're not allowed to have any distractions in the front of the vehicle to avoid endangering yourself and others while driving. There is one exception here - if the DVD you're looking to install has a kill switch which allows it to work only when your vehicle is is parked. Back seats on the other hand are allowed to have TVs and DVD players.

Installing a Super Loud Sound System or Exhaust System: You already know this - unreasonable or unnecessary noise or smoke coming out of your vehicle is illegal. If you want to be sure you're within legal limits, carefully read through an exhaust's (or other performance products') specs.