Looking at heated flooring... not sure what to buy as far as watts... what is the difference between 1750 watts/ 450 watts?

What's the difference between 1750 watts and 450 watts... will having a higher watt make my heated floors warmer?

1300 watts. Watts is consumed power so at higher wattage it will heat faster (approx. 4X) and if it is cold, will possibly heat them better. With a thermostat, once the desired temp is reached, it will cycle the elements. You cannot convert watts to amps without knowing voltage. For example, @120 VAC, 450 watts is about 4 Amps and at 1750 is about 14 amps. Think of an oven vs. a slow cooker, High wattage oven and low wattage cooker, both will do the job, just longer at lower wattage.

Typically floor heat is rated in watts per foot. Most is 10W/sq-ft.

Only you can tell us what you were looking at. There is no way for us to tell from here why one was 1750 and one was 450.

The size of the room it is being used for is the way to determine what size heat you require. If it a small 4x6 room you don't need 1750 watts of heat.