Guts somehow ended up in the middle of Tokyo in Tokyo Ghoul verse.

This is current Guts in his perfectly healthy body along with his Berserk Armor, Dragon Slayer and his usual standard equipment.

Scenario 1: Guts gets recruited into the CCG as a Dove. Guts' Dragon Slayer is coated with Kagune and is trained how to kill a ghoul by the CCG. This takes place where Kaneki found Rize at Kanou's laboratory. Guts must kill or capture Kaneki. Guts will have his Berserker Armor, kagune throwing knives and a LAB COAT!!

Scenario 2: Guts is kidnapped by Eto and turned him into a Koukaku Ghoul. Guts is then ordered to kill the Qs Squad, this is Qs Squad before Haise (Kaneki) left the Qs Squad. Guts will have his Berserker Armor and Dragon Slayer.

Q: How strong would Guts be if he becomes a Ghoul? And what rank would he get?

guts as a human is about a special class/Half human level as a ghoul he would probably start out as a SS Rated ghoul at least

Scenario 1: If he has the Berseker armour he can probably do it.

Scenario 2: He could beat the Q’s at this stage. They managed to take down Noro at this point, which shouldn’t be overlooked, but Guts is incredibly skilled and as ghoul would be even harder to kill. He’d probably cleave them all in half after a brief but intense fight.

Definitely SS~. Has the capability to become SSS if he cannibalised.