Symptoms: After driving for about 40 mins OR heavy boosting she likes to make the coolant completely disappear lol. No leaks anywhere, bled it good. Seems the coolant system is being pressurized and its pushing coolant into the overflow and then out of it.

I vote head gasket [I changed the radiator cap with a known working one]. What do you guys think? There is SLIGHT white smoke here and there at idle or heavy boost.

Now, if it is the HG, it will be replaced by an OEM MLS unit, SHOULD I GET ARP HEADSTUDS? I was once told "It is cheaper to replace head gaskets then bearings or rods" meaning, if you get a MLS HG and ARP's if you get knock the next weakest link will go. What do you think?!?

i have the same problem right now and i have narrowed it down to the HG i did a block test (the blue stuff that turns yellow) to confirm this... and ARP's are never a bad idea. if you go with a MLS HG you will ahve to get the head resurfaced, but if you just want a quick HG change the stock gasket is the way to go. and if you arent running high boost it will be ok

Have you checked your oil yet?

Water in oil or vise-versa may or may not show up untill it gets really bad or depending on where it starts blowing out at... it hasnt happened in mine yet but it is possible to push coolant and not be mixing you coolant and oil. i completly blew a stock HG before and never did my fluids mix it blew out my stock radiator top though lol

this seems to be very common with Cometic HG which is what i have... ill be going with a MMLS next. so i wouldent recomend cometic

That kind f by failure is usally installation error and by not doing the correct prep work. That being said if your not going crazy with your setup I would recommend a mitsu composite by and arps.

sounds like headgasket to me, lil crack in the headgasket will let pressure from combustion chamber enter the water jacket and that air has to come out SOMEWHERE. i knew someone who's top radiator hose kept blowing off from the radiator. when you took off the cap, you'd feel bursts of air at idle.

i'd go with stock mitsu gasket + arp studs.

After going through 2 full "tanks" of coolant trying to get her home I was so paranoid that the very next day I did an oil change, no signs of coolant in it!! The coolant has no signs of oil either.

So far I have ordered:
-OEM Valve cover gasket
-OEM Thermostat
-OEM Thermostat housing
-Gasket

Today I will order:
-Mitsu MLS HG
-ARP's

The reason why I want the MLS is because I plan on boosting around 19psi on the 16g, and eventually plan on going bigger, how does that sound??

Do you guys think I should replace the valve seals or anything like that?

Did some searching through my garage and FOUND some BRAND NEW ARP head studs and a Cometic MLS HG [86mm 0.51"].

I hear Cometic = Junk. True or Not??

The ARP's I found are 11mm Part # 207-4203 I am trying to reference the part number to see if these will work.

I guess I had these from a previous DSM build. Currently I have a 95 GST, stock engine [seven-bolt]

Cometic MLS's are OK. I'd stick to Mitsu MLS. I know people who run the Mitsu MLS up to 55psi. Where the HKS, Cometic, and everyone else failed. And on erix's not, Yhea with a weaker composite gasket, you are more likely to kill that before you kill something else. But if you know what you are doing as far as tuning, and trying to actually push high boost, the stock composite will keep failing.

Have you checked the turbo for play? Correct me if im wrong but isn't a 16g WATER and oil cooled? You could be buring the coolant up through the turbo.

you could take it to a mechanic and have them hydrocarbon test the coolant, that way for sure you know the head gasket is no bueno