So i looked at this one more time closely. I am exactly 4 degrees off. so it is decision time, should i do it or not (i.e change the chain)? more importantly, will i see any performance difference? and could this be the reason for the exhaust smell?

advice please guys, thanks for everyone who contributed untill now.. you guys have been really helpful !!!

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1993 300E, 2.8 M104 .....