how much weight a vehicle can tow/pull is determined by Horsepower,Torque the both or what?

Towing capacity is determined by the manufacturer of the vehicle. Most all vehicles can be found on kbb.com

Well, I can't furnish you with any specific numbers: but horsepower is the ability of an engine to do work. Torque is what we feel when we hit the accelerator in a car or truck.

Torque is pulling power.

Horsepower = speed. In other words, if you have 300HP, the car or vehicle will travel a quarter mile in a set time...say for example 15 seconds even.

Torque = how hard the vehicle is running.

Finding out info like this can be easy ( http://www.google.com/ ) , try looking your list up at: http://www.trailerlife.com/towratings/tr_index.cfm

Tow ratings are based on a lot of factors, some of which are suspension, transmission type and strength, tire ratings, brake capacity, torque and horsepower.

how fast do you want them to go?

you cannot base how much it can pull simply based on power/torque stats