Thank you, 400E.
I changed the oil to Mobil-1 right after I got the car, even the transmission fluid is Mobil-1 ATF now, I have also put in injector cleaner twice.
I timed it tonight, actually not bad as I felt, only 1.5 second, probably the same as your car? maybe it was just designed in that way, then I will just live with it. The car fires up the fastest I have owned is my current pushrod V6 Ford Explorer, I feel it takes as little as 0.1S to fire up, it's 5 years old, still on its original battery.
I do recall my previous Volvo 850 also required a little bit longer cranking, maybe this just European engineering.
99 BMW 540i 6-speed 110K Km
03 SAAB 9-5 wagon 80K Km
92 400E (Sold) 245K km
Still missing the days with the Benz, it kept me busy.