Motorsport homologation requirements in the 1970s led to the road going 911 Turbo that we know and love today. The car was designed and engineered to win races first and foremost.
Although the 911 Turbo has not been associated with a race series for decades, the pattern was set with the original 930, every new generation of the 911 has included a Turbo version in the lineup. The 911 Turbo has always sold well too; ~5,000 964s, ~6,000 993s and ~22,000 996 Turbos.
Porsche Shop – UK based online store that stocks parts for all Porsche models, this is a great site to find most parts or even just to get an idea of prices before buying a car.
Rennlist Forums – International Porsche forum with owners of all Porsche models, get great advice, help, find parts and even trade cars with other enthusiasts.
JZM Porsche – UK based specialist dealer that sources and sells collectible Porsche 911s from all generations.
Top Gear review of the Porsche 911 993 Turbo.