Your car looks to have been modified for you. That looks like a Maxton Design Rear Diffuser and Spoiler Cap, You have some wind deflectors is there a spoiler on the front as well
@paddy6789 beat me to it...
With regards to rubber if you are not suffering badly with wheel hop then stay with these till you can afford decent rubber, if its bad then I am afraid you have to control your right foot or buy new rubber.