Complex sentence: The 911R had a very limited production (20 in all), as this was a lightweight racing version with thin aluminium doors, a magnesium crankcase, twin-spark cylinder heads, and a power output of 210 PS (154 kW).
Split into simpler sentences: The 911R had a very limited production (20 in all). This was a lightweight racing version with thin aluminium doors, a magnesium crankcase, twin-spark cylinder heads, and a power output of 210 PS (154 kW).