The ZDZ became less expensive very recently, since Troy Built models pick up the line. Still at 375$ US, it's more expensive than a DLE30 cc; pretty much on par with the SAP sans muffler. ZDZ cost me 550$ when I bought it 4 years ago. OUCH!!!!

The most attractive attributes are rear intake and rear exhaust. It will turn a 20x12 with good authority on pipe (around 7K)

The rear drum intake (as opposed to simple reed intake of the others) is heavy by comparison. There is also quite a bit of extra meat on the case of this one. If one had access to a milling machine, I am sure this engine's weight could be dropped down to below 40 ozs. Remember that a YS170 weighs in at around 36 ozs, engine only, which isn't exactly light. But guys are running the ignition version of the engine with little problem