http://www.vhtpaint.com/products/flameproof/

I bought a FMF Fatty for my bike and due to the bloody road salt in England atm it is already starting to show rust, so I managed to track down this stuff! Looks absolutely amazing!!!

Actually says it can be applied to PISTON DOMES!!!

I tried a similar product on the piston crown 25+ years ago on an aircooled '84 KDX200.

No noticeable difference. Unfortunately, it did not receive a long term test as the motor melted down when I encased it in mud during an enduro. I rebuilt with a 240 kit and an unpainted piston. Never used paint on a piston top again.

My personal opinion is that there are no real gains to be had in painting the piston. Since the paint maker has never tested it in your application, there are unknown risks.

I'd put the money as a downpayment toward something that will make a real difference, like a fresh set of high quality tires.

As for painting the pipe, that paint would be great for touching up a stock pipe. But I think it is going to be difficult to get a nice uniform finish from a rattle can on an FMF pipe. Steel wool and WD-40 are what many use to freshen up their FMF pipes, but it never seemed worth the effort to me.

worst case use sand paper to keep the rust knocked back. or maybe just paint the front section of the pipe...I have no Idea how bad your pipe is.. you ride that on the road so rinsing down is out of the question as you use it every day probably??

My bike gets cleaned and polished after every ride but that is only about 10 -15 times per year

I want to ride it more often, but after putting a brand new pipe on and having it rust like that... hrmm. I've ordered the stuff anyway so I will let you lot know the results!

how about spraying wd 40 on it and making an extended mud flap for the front fender to keep the salt off it

In the week I've had the exhaust I've already gone through nearly a can of WD.

I used header paint (similar to the one in your link) on a gnarly. First I scrubbed the rust off with a brass wheel on my drill, sanded the rusted area, and then painted the sanded area. I baked it as per the instructions on the can. It held up fairly well, and looked a lot better than it did rusty. Give it a shot, it doesnt sound like you have much to lose.