My favorite Z has to be one of the 74 roadgoing / competition "Super Samuri's" built in the early 1970's.
http://www.sportscarmarket.com/columns/profiles/race/4834-1973-datsun-240z-super-samuri
"Among U.K. Datsun enthusiasts, particularly those with a fondness for the 6-cylinder Z series, there is no bigger name than that of Spike Anderson, legendary proprietor of Samuri Conversions and the man responsible for a succession of Z-based racers in the 1970s, most notably Win Percy’s famous “Big Sam.” Very few cars are so famous that they are commonly referred to by their registration number, but FFA196L is one such and rightly so, as it was the first Datsun 240Z to benefit from Spike’s attention, going on to become a motorsport legend. This was the first car to carry the ‘Samuri’ name, a deliberate misspelling, as the Samurai trade name was owned by another company. In 1973, Spike purchased a Datsun 240Z registered FFAl96L for his personal transport, but the car did not remain standard for very long. What would turn out to be a lengthy and ongoing program of tuning commenced with gas-flowing the 2.4-liter, overhead-camshaft six’s cylinder head and raising the compression ratio, which was followed by ditching the standard carburetors in favor of triple Weber 4ODCOEs. Mangolesti supplied special inlet and exhaust manifolds, and in this specification, maximum power increased from 150 to 190 horsepower. Suspension improvements consisted of lowering the car by 40 mm and replacing the standard shock absorbers with Koni items. The weak braking was addressed by using ventilated discs and four-pot calipers from a Range Rover. Fitted with a deep front spoiler and refinished in distinctive red/bronze livery, Spike’s “Super Samuri” soon gained the attention of the motoring press. Various magazines tested the car and gave it rave reviews, typically achieving performance figures of 0–60 mph in 6.4 seconds and a top speed of 140 mph."
http://www.sportscarmarket.com/columns/profiles/race/4834-1973-datsun-240z-super-samuri
http://zhome.com/History/BigSam.htm
http://zhome.com/History/BigSamIsBack.htm