Recommended LED and power supply

An Help to seek the best accessories for this Shield.
I would like to connect 3 LED 4W GU5.3 MR16 12VDC (for dimming) to the 3 shield outputs and I would like to use an external power supply but I don’t know which one to buy.
Can you suggest one?
For this choice there are specific aspects to be careful?

Thanks!

We’d suggest to check with the supplier that sells you the led’s.

Then I correct my question.
In my project I don’t want to use a strip led but I would use the three channels separately and connect them to three power LEDs of about 4W each (to be well below the 2 amps when the Vin is 12 V).
My application will have to adjust the brightness of the three led by changing the pwm values in the arduino uno.
Can you recommend a Velleman products (power leds and eventually a led driver) that fits my needs?

Thanks,
Michele