If you tinted them black they will stand out like a sore thumb on the back of your silver/grey Leon. You'll have a mass of silver with two big black things staring at you!

Have a look at the Raid LED lights if you want to change yours. They look very OEM, but fresher and with the LED's for the tail lights. Very smart, but wont ruin the look of your car.
 
Yeah, that is the same price I have seen them for, they are on my 'long term' shopping list as a bit of luxury item, one of those finishing touch jobs!:)