Painting underside of my car!

[muhuha]

In need of some help. I've got bits of my car to paint such as bumper bar, ARB and some brackets here and there. For small bits i've used spray stonechip paint which seems to leave a nice finish but not sure how durable it'll be so for the bumper bar i'm not sure what to do, i hear hammerite is not up to scratch, i was considering powder coating/stove enamel but this will cost god know how much.... Is there a paint i can pick up from B&Q or like that'll be upto the job and leave a soft finish?

[LuS1fer]

I'd use POR 15 myself. Used it on the inner arches of a Camaro. Best stuff but get the solvent to get it off you after. You also need to use the whole tin fairly quickly as it sets solid eventually.