Either of those would work, too. I use aerosol cans...they take alot of unnessicary flak from alot of people...any well stocked hobby shop should have it, even some not to well stocked shops'll have it.
First, you'll want to prime the car. There are about a dozen good, usable primers. My favorite is the Model Master Lacquer white primer.
You will need a clearcoat. Testors 1261 is their pseudo-lacquer and that won't yellow. It's safe to put over the French blue and the Lacquer white which you'll also need to buy.
With spray paint you want to stay about a foot back from the car and move past the entire car in one stroke. Don't try to cover it all in one stroke. The best paint is done in many small coats.
The blue will take several days to dry. The basic rule of thumb is that when you sniff the car and can't smell the paint anymore, it's dry.
Slixx decals are some of the best out there. What I've discovered, after using about 20 of their sheets, is that when you put it in the water, it's ready to use when the paper uncurls itself.
I use a damp paper towel to press the decals into their location and smooth out air bubbles. Most people tell you this is wrong but I've decaled about 75 1/24 cars and never had a problem caused by that.
You will want to buy some MicroSol, a decal setting solution. It helps you get decals into odd shapes or crevices. Be carefull though, because some Slixx decals have bad reactions with it. You won't know until you start if the sheet will give you issues with that.
I suggest using the Slixx logo and the sheet name and number, which is also a decal, as practice. The inside of the trunk area is a good place for that (Unless it has an opening trunk)
Hope that helps, and I'll try to answer any more questions you can come up with