I don't think you'll get them that low with the basics. Plus its a PIA driving around with it that low! Trust me. I got mine dumped with Tein Basics and it has maybe 4 threads left on the front and 6 threads on the back.
You can go pretty low with the Tein coilovers. I actually wish that that front would go lower, I plan to take off one of the adjustment rings on the front tower to get another 1/2-3/4" lower. I had mine set all the way down in the front and 3 threads from the bottom in the rear and it's pretty low. My gas tank bar and exhaust can were 2" from the ground. It is a PIA for sure. No speed bumps almost no driveways there were even a couple uneven road surfaces were I scraped. I drove like this for the last 7 months. You just have to think ahead and don't go anywhere where you're not familiar with the roads/driveways. The "street view" on Google maps was a great tool.
I've had my Teins on since 2005 and I have a 4WD. No problems at all. I have only put about 20K on her since then too so take that into consideration. I have only raised it up for maybe 4 months of that time too. I'll put my stocks on whenever I'm going to need to carry some people, driving a long distance or doing some work on my 20's.