No different , Only in Egy-A and Egy-B weapons .. Because B is rare , Attack is more higher ..
@Set , in iSro same price of both .. Which means it has to be same , Just different head and the gear itself :-)
destruction 4 part gives +1 more power to your 4 part(if they are +5, it will shown as +5 but the stats are like if it would be +6) 6 part gives +2
immortal 4 part gives +2 and 6 parts give +4