first of all rustoleum is only for metal. it will not stick to plastic or pvc. so make sure everything you are spraying is metal. basically glaze is going to give it a glossy finish. the lacquer is going to give it that finish and provide protection. i would use the lacquer but maybe try it made by american tradition/valspar.Whats better? clear glaze or lacquer?
Valpsar/American Tradition also has a ultra gloss clear coat which can be used on plastic or metal. And would work on top of what you already applied.
there is no need or advantage in using both. The clear glaze is better when the item being finished is liable to knocks, as the lacquer is liable to chip more easily.
As it is a stereo I would suggest this is an item not likely to receive many knocks, so the lacquer will give a hard bright surface finish which should last well.
The finish from the glaze will also be (not quite as) good, and have the durability its greater flexibility will give, but the shiniest finish will come from the lacquer.
Obviously up to you...
Hope that helps,
The only paint I would use would be the Fusion paint made by Krylon, which is designed to stick to plastic. Other paints contain solvents like acetone, which may distort the plastic--even melt it!