Thanks for the great insights!
About 1/4 of a liter of coolant has been lost over the past year. The smoke seems to be slowly getting worse.
The exhaust doesn't have a sweet smell. I don't know why, but it really just smells like normal exhaust. It smokes whether the engine is cold or hot and more so when the engine is revved.
The spark plugs all look like the one in the image at the bottom of this post - there wasn't one that was more clean than the others. They all looked almost exactly the same. The buildup that is there seems to be really stuck in - it would require a knife or metal brush to scrape it off because a fingernail is too soft. I'm guessing it's just carbon. The plugs probably have less than 1000 miles on them. I believe Dr.Hess's theory is that the cylinder with the leak will be cleaner because the coolant would wash off the carbon - right?
The way I figured out that the smoke contained coolant was by cupping my hands around the exhaust for about a minute. There wasn't really any residue, no wet feeling, and no oil or strong gas smell. However, there was a very unmistakably strong smell that reminded me of those cough drops that numb your throat. So I started googling for the ingredients in those types of cough drops and one of the main ingredients is menthol, which from what I read, has a very distinct smell. It turns out that some antifreeze coolants use menthol, but many of the newer ones use a variation that has a similar chemical structure. I dipped a rag in the antifreeze and it just smells sweet, like normal antifreeze. I'm guessing running it through the combustion chamber is what caused the menthol smell to come out. My hands reeked of cough drops all day - even after washing them twice!
So in my mind, I'm convinced that there is antifreeze going through the engine and exiting the exhaust and causing the smoke.
Now the question becomes, where is the leak coming from. Is it possible that there is another location where coolant could get in other than the headgasket?
Mr. <@¿@> mentioned that it could be a cracked cylinder wall or a cracked head - so that's one possibility.
Dr. Hess mentioned that intake system has no coolant so I guess we can rule that out (it is supercharged, but the coolant system didn't require modification for the supercharger install).
I have not tried the combustion tester kit from autozone. Would that help me pinpoint the leak's location, or would it just tell me that I have a leak, (which I already know)?
I also have not tried the bleed-down compression test. Perhaps that would tell me which cylinder(s) could be affected? I can do that next weekend.
BTW, if anyone wants to see what the smoke looks like, I put a short video clip here:
. It was windy so the only way I could get the camera to pick up the smoke was to rev it a bit.
The main goal is to determine the leak location so I can make a good decision on what to do about fixing it. If it turned out to be something not too complicated I will just do it myself. However, if it's really a head gasket or cracked wall, then I don't have the tools or time to do it so I'll have to ship it somewhere far away and pay lots of dinero

anic: