I have this black trim around the bottom half of my doors like in the photo but I've just noticed that a lot of modified polos dont have it and look a lot better (i feel anyway) how would i go about taking this off and if i do will it not have ugly holes for clips and such underneath like most cars do and whats the best way of covering that up?

They are stuck on with double sided tape, so they don't leave nasty holes in the bodywork, there are various methods of removing them, just pull them off (risks damaging paintwork) use a hotair blower to soften the adhesive, or use some dental floss/thin fishing line and cut them off, what ever method you use, you'll be left with a sticky residue, I used a petrol soaked rag and an old credit card, but probably the quickest method is to use a "Toffee Wheel" in a drill (plenty on ebay)