The M1 engine uses Diesel as well (aviation, Petrol, Kerosine, Diesel, I did read the the Australians are using diesel in theirs), you forgot to mention the M1 is dangerous to be behind (not allowed to tow other M1 tanks - one was set alight and destroyed when being towed despite the tow vehicle stopping frequently to allow it to cool down), it has a massive thermal signature and is a real fuel hog when using JP8 the usual US fuel.
The vast majority of MBT’s use conventional diesel engines.
The KV had a larger gun than its contempories (1939) firing AP that could defeat any tank in the world at the time at ranges they could not even scratch its paint.
What do you class as long barrel as well the M1 uses a 120mm L44 most other tanks use 120mm L55, hmm the M1’s gun seems a little short compared to the rest.
Depends on Mk of Centurion, but what was that thrown in for.
The Panzer IV depending on Mk had three 75mm guns - 75mm L24, 75mm L43, 75mm L48 which one you referring to, you just repeated two points I made (although modern MBT have 3 or 4 man crews), seemingly ignoring the rest with are the same claims you made for the tiger but it entered service earlier (the Panzer IVG).
The Crusader no it was designed and entered service two years after the T34.