Lie I said, you could use them and never have a problem. Bt theres also that chance that they could fry the mosfet.
The Smoktech tank comes with a 1.5ohm Dual Coil, which could potentially fry your mosfet, but only potentially. Your using 1.5ohm cartos now and its okay right now, but still be careful bc that doeant mean that same carto wont fry it a week from now. If your going to keep using them I recommend getting a multimeter so you can check them. Cartos can slightly drop in ohms from use and that slight drop could be enough to push it over the edge and fry it. Also all cartos arnt always their stated ohms. Most can be +/- .2ohms. So if one is actually 1.3ohms or drops to around there from use, they you really risk it frying your mosfet. Thats why I recommend 2.0ohms bc then if it does drop, the slight drop is less likely to kill your PV.
Using a multimeter will allow you to check the ohms to see what the carto is actually at, and then you might be able to catch a carto that isnt the stated ohm or drops in ohms from use, which could have potentially fried your eGo.
I think youll like your kGo alot more than the eGo. The kGo is a 3.7V device instead of the 3.3-3.4V eGo. 3.7V PVs handle the lower ohms better and you should have no problems running 1.5 and 1.7ohm attys/cartos on the kGo. The kGo actually comes off the charger at 4.2V then drops to 3.7V after using it for alittle. The batteries last a long time too which is always a plus and most kGo users get a full day from one battery.
The kGo will work great with the Smoktech tank. I also recommend trying the Ressurector cartos on your kGo. I use an E-Power which is similar to the kGo but uses non-proprietary batteries, and the Ressurectors are the only cartos I use.
I have one of the Smoktech tanks too and it works well. Personally I only like dual coils in the 4-5V range, but you might like them. If you want to use something else nesides the dual coil that comes with the tank, CCV now sells pre-punched Ressurector cartos that have the metal base to be used in the Smoktech tanks. I like the Ressurectors in the tank alot more than the DC that comes with it.