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The front door speakers on second generation Neons (2000 and up) are 6.75". These are sometimes called "oversize 6.5"" speakers.
8 ohm
Haynes repair manual, Dodge Neon 2000 thru 2003. Book #30036
Remove rear seat, them remove rear deck to get to the speakers.
6"X9" speakers in the rear 6.5" speakers in the doors 3.5" spearkers in the dash
Rip the old ones out. Then replace with new ones.
there are NO speakers in the "rear" doors of a Neon.
Haynes repair manual, Dodge Neon 2000 thru 2003. Book #30036
no a 2001 dodge neon motor will not work in a 2000 neon
Heater Core is the likely culprit
Where is the oil sending unit on a 2000 dodge neon?
A 2000 Dodge Neon does not have a maf sensor.