With the proprietary twin spark technology, Bajaj are able to run their engine, with a leaner fuel setting, yet able to get sufficient power from the same. Yet they may run slightly hotter than your average engine, which causes the engine block to loose it's colour after a few years, compared to the rest of the engine. However this is a very small price to pay for an otherwise powerful yet fuel efficient bike.
The new model comes with many internal reinforcements which make it a superb value proposition. Go for it. Pulsar 150.