Sounds like your friend has things slightly confused... Let me lay the ground rules down for you, so you won't be confused any longer.

Black smoke, USUALLY means rich, also means a buildup of carbon inside your combustion chambers / cylinders (Also caused by running rich, OR car not burning all the gas in the chamber.).

White smoke (that does not stay in atmosphere very long) is GENERALLY water vapor, sometimes this will go away by the time the car warms up, IE: Just condensation in the pipes
If it does NOT go away, it is most likely a blown head gasket, in which case time to get a new one.

White-Grey/Grey-Blue Smoke (that Stays in atmosphere for a while)- This is generally bad oil rings when this happens you may have a week or 10 years before they go completly, and you have to replace them... Depending on how bad the smoke is, that's how bad the rings are.

Now, onto your post.

Since you smell oil mixed in with gas, that would prompt me to tell you: Goto a automotive shop, and ask them to perform a "Leak-Down Test". Ask for that by name, this is NOT the same as a compression test, some places don't know this. A leak down test involves putting compressed air inside your cylinders and measuring how much of it leaks out.

I agree that a little puff every now and again from high shifts is nothing to worry about, in fact, it's mostly normal...

The black smoke thing is not normal, I suggest getting new plugs/wires, basic tuneup shit and see if that doesn't help out any. Generally if your mostly stock, you shouldn't be puffing out black smoke. Black smoke means you're not burning all the fuel inside the chamber, and hence everyone telling you you're running rich. Technically you're not running rich, you're running normal and your ignition system isn't keeping up like it should.


Hope that helps.