Definately impressive!!

alot of people usually don't realize how much effort and cost goes into extracting such hp levels from naturally aspirated engines.

Just a comparo to show what a feat this is;

The F20C produces the highest specific power output for any naturally aspirated 2.0L piston engine in a car priced under US$100,000 at 123.5 hp (92.1 kW) per liter.It held the record for producing the highest specific power output for any mass production naturally aspirated piston engine until Ferrari released the 458 Italia in 2010, which produces 124.5 HP/L.(its a 4.5L v8)

So this 126hp per liter hybrid is nothing to scoff at and quite a feat for an old school NA engine to accomplish.