RENIX (Renault/Bendix) is the fuel injection / engine management system used in XJ Cherokees prior to 1991 (87-90). A 95 would not be Renix to begin with and as long as you stick to 91-95 parts you should be fine (96 went to OBDII). Before you do anything with the engine, check the flex-plate, a loose or cracked flex-plate on a 4.0L I6 will sound almost exactly like a bad rod knock.
HO stands for High-Output but is basically meaningless since every 91 and newer 4.0L I6 is an HO. So they are only "High-Output" in comparison to older Renix engines and it isn't that big of a difference anyway.