the giant perfect cell is a buffed out to the max cell. he's big as a building. is he a match for the oozaruus?
Perfect Cell could beat any version of the Oosaru except for Golden Oosaru. But it also depends; in theory if Goku during the battle with Perfect Cell were to turn Oosaru, Cell would loose because transforming into a Oosaru means multiply the power level by 10. Perfect Cell would be over powered dramtically, but that doesn't mean he can't win. The Oosaru have a certain weakness and that weakness is the tail. Perfect Cell is master of his Ki energy and directing them, hence an attack on the tail. He could even use his own strength to take out the oosaru's by just grabbing a hold of the tail and paralyzing the oosaru. Other than that it's quite practical for Cell to win.
On another note; Vegeta is the only known Oosaru to maintain total control of the Oosaru form. He's power multiplies by 10 folds, plus he gets to keep his speeds & special attacks. Vegeta would actually be more dangerous a foe than any other sayian (besides Broly) to turn into an oosaru! However; let's not forget, Cell does have Sayian genes, and has the ability to morph his body into a giant as the size of an oosaru. I'm sure his power does multiply by 10; but that didn't do any good against an angry Super Sayian 2 Gohan. Perfect Cell should know better not to turn into a giant; he's actually alot more powerful as Ultra Perfect Cell.