from what i have read in the maual release. P5 has all the P4 features and then the aditional addon's so yes if you use p4 models you can run them back and forth. as to useing the P5 models, I would assume (gota love that word ROlls eyes) i would think not. Im sure they will have features and mods not saported in P4. as to cloth, manual states you can use cloth to modify/morph clothing and save as morphs so if you do so and save in P4 format should be useable in P4. Go over to CL and dl the manual it should answer a lot of this questions for you. Hope this helps laters Vel