Diddy’s legal team is gunning to blow up a major moment from Kid Cudi’s testimony — asking the judge to strike everything about the disgraced rapper’s Porsche firebombing … claiming it’s all based on suspicion, not proof.

TMZ has obtained the legal docs filed in Diddy’s criminal case — where his lawyers argue Cudi’s claims about Diddy’s alleged involvement in his 2012 car explosion are nothing but opinion and shouldn’t be allowed in court. In short … they’re saying Cudi thinks Diddy did it, but there’s no hard evidence, no confession, no receipts.

As we reported, KC told the court last week he ‘knew’ Diddy had something to do with the Molotov cocktail attack on his Porsche after ending things with Cassie — but admitted there were no witnesses, fingerprints, or proof linking Diddy to the arson.