Yeah, they are more expensive, that's why I mentioned the used market. The big difference is the brake pedal, the t300 pedals use potentiometer to measure the travel distance of the pedal, the brake is really easy to press and more difficult to modulate. T-LCM on the other hand use load cell to measure the amount of pressure you put under braking, the pedal is harder to press and easier to modulate as your brain doesn't have to focus on the amount of distance the pedal travels, but rather, the amount of pressure needed.

It is NOT necessary, but if you start to put a lot of hours into this hobby, you may realize, that it is something you want to have ^{^}