I had one of these fitted to my 98 2.8 TDe, and when the central locking played up, Nissan flatly refused to even look at it because I had fitted an alarm not Nissan.
Took it to the folks who intsaled the alarm, and they told me the fault was in the central locking not the alarm, and Nissan should fix it.
Nissan declined to come to the party as long as the non Nissan alarm was fitted.
So folks, before you go down this road, ensure you will never call upon Nissan for any work on your car, cause they'll knock you back.