Looking at the design, they have the same lowering done by dropping the spring perch. You drop a car on Tein SS or those Tanabes, you will lose shock travel. Those, from looking at it, are Tanabe's equivelent to the Tein BASICs.

The Tanabe system is also a 6/4 spring rate, while the Tein BASIC and SS systems are 8/6. The SSs have adjustable shocks, which are very nice.

Depending on what he wants, the Tanabe will give a little more everyday stiffness, but the Tein's will have much more support. Both are made from steel and have twin-tube shocks, so they're not the best of quality, but they're both good. I'd rather have the Teins though.