LED's

[Bradley8988]

looking to buy a few red LED's to replace the stock ones in my case. what size should i get and as i dont really understand anythin about them is there any differant variants i should know about?
What are the differance between these?
http://www.ultraleds.co.uk/basic-leds-leds-c-103_25.html?filter_id=11&sort=2a

 

[Bradley8988]

well i had quick look but all i get up is all the chav car bits. is it the 3mm ones i should be looking for? also the brighter the better i guess. theres ones with free resistors on there, will i need them?