I personally use the Turtle black in a flash but i have heard the meguiars it good to but more expensive
Be very careful about getting it on your paintwork as it makes polishing twice as hard & not so good at the end
I peronally use a cloth or a sponge, spray on that & then apply to the plastic but BE VERY carefull
You can also use on the heater control/stereo & most of the inside if you like the glossy look
I nornally buy from the big asda stores as it under 2quid in there - halfords charge nearlly a fiver for the same stuff
I am sure there other stuff & other have other suggestions but thats my perosnal prefence as its does more than just your tyres
Turtlewax Black in a Flash 500ml from Halfords Price £4.99
If your interested follow the link - its Halfords but gives you an idea
Post your pics when its all clean & shiny
Enjoy & good luck