Ok basically keep it nissan, for example MSD blaster coil alone it seems to have less of a spark when swapped directly for the nissan one than when left stock. The MSD coils etc need drivers to work properly, the stock nissan one is not upto the job.
The rest of the ignition system would need refreshing/cleaning. Leads are usually fine, not had a prob so far, rotor arm and cap should be changed/cleaned - even if they are a month old. Its cheap so do it! Spark plugs as well, gap to 0.7mm try to avoid the iridium tiny point plugs they just seem to in my experience blow out sooner than normal 'traditional' style plugs. If you have a fairly accurate boost gauge with vacume, at idle around 1000rpm you should have around -0.45 to -0.5 bar. If its less say -0.35 to -0.4 it will be tough to get a good idle, and most probably wont be idleing very well anyway (too rich/retarded etc to compensate)
Fuel pressure regulators should be set at 3 bar and avoid FSE PBV - this again is my opinion, I feel that stock nissan ones are perfect for the job they were designed for unless your way beyond the caperbilities of the e-manage anyway.
Vacume pipes should be tight and not old/splitting worn etc, if your going to new boost levels cable tie them on. I get them popping off causing all manner of strange problems.
Attention to detail is critical, in summary if I for example come along to map a car that has lots of hidden issues it makes mapping a nightmare and ultimately costs you more in my time, as usually youll have to come back again once the problems have been solved.
This is in addition to any other basic servicing, such as oil and water checks. Trust me when I say if the car has any weakspots when any mapping takes place they will show up sooner or later.
Ed