What is the avg life expectancy of a infinti g20 or I30

Both are the most reliable Infiniti. The G20 91-93 was made for turbo but would not pass smog plus the price would of been out of the target buyer. The I30 was in 96-99/1/2 the 2nd most reliable motor rated by Wards auto world magazine. The starter maybe or maybe a ignition coil(s) is about the only problem you will have with the motor.

None, if is not going to be a classic l will not invest on any of those cars. They are Rich Man Econo Boxes or lets say Rich People Datsun. Is not worth what they are, a hyped up Nissan Sentra. Not good return on investment. Unless you trade it for another Infiniti.

l have a 94 Pontiac that is holding up pretty good and is daily driver even on the snow of the great north in MN. The molding and seats still in one piece.

l have an I30T & its 12 years old. l have replaced 2 sets of tires, 3 rotors & the catalytic converter. Other than that, it runs like a top & yes l do regular maintenance, like oil & filter change every 3K miles, gas filters, tune ups etc. Whatever the manual says to do. Nothing leaking, nothing broken & everything works. Still a pleasure to drive.
By the way, the fit & finish is far superior to a nissan, that is why it costs so much more. l got well over 100K miles on it now & shooting for 200K.