electronic cigarette vs cigarette

i started smoking cigarettes at age 24 or 25 (started with marijuana)

i've kicked the weed, but i still enjoy smoke breaks. my question is a two-parter:

1) cigarettes are said to reduce stress, but how much of that is related to plaque poisoning?
2) how unhealthy is it to drink coffee while smoking? the combo feels great, cuz i was told the two stimulants expand and contract your cells at the same time, but would it be safer to only enjoy one vice at a time? if i want to do both, should i only drink decaf coffee so i'm not overloading my nervous system?