I too have had a problem with the rear cam oil spray bar on my 1993 Nissan Primera SLX. The problem exhibited itself as a loud squeak that happened occasionally when the engine was cold. Due to the noise becoming very loud I eventually took it to my Nissan dealer and he removed the rear spray bar. He pointed out that it was blocked and I might need to replace the cam followers and even the cam, some 900 euros. I couldn't afford to pay for this work so asked him to put it all back together.
I returned home and removed and unblocked the spray pipe myself. This was fine for about a year, but it happened again recently and I removed the cover and again proceeded to unblock the spray bar, but thought I'd remove the front spray bar and check that although it has never had a problem. When comparing the two spray bars side by side I noticed several quite significant design differences, apart from the shape. They were obviously different manufacturers and the oil feed holes were of different diameter. The holes in the that had the blockage problems were quite tiny compared to the good one. I decided that I'd widen the holes to approximately the same size as the other spray bar. This has fixed the problem and the engine runs quite smoothly now. I'm sure Nissan knows something about this problem and is keeping quiet.
I would say that this car is the nicest and most comfortable car I've ever driven and I have done 60000 miles since I purchased it.
I hope this may help others.
A little unfair that, giving the car a blue face, then saying that you are going to buy a newer Primera :-( I own a Primera Sport+ VT6 A and they are a superb car, really smooth and tight as a drum, even at 105,000 miles, but change that engine oil every 3 to 5,000 miles or at least twice a year and use a good quality oil, as the engine is chain cam driven and good clean oil is essential - unless you want to end up having to replace the timing chain and tensioners that have failed due to lack of lubrication. Lack of frequent oil changes is probably the reason for the camshaft spraybar holes becoming blocked on your old car, I can't stress enough the importance of clean oil with these engines. Also check the CVT Auto box fluid level regularly and ONLY use NISSAN NS-1 CVT FLUID - ordinary Auto Transmission fluid WILL eventually damage the CVT gearbox.
With the SPORT+ or SE+ (Sept 99 on) make sure that the Xenon HID (High Intensity Discharge) headlamps work properly, the bulbs are gas discharge and cost over £60 each and the headlamp units themselves, over £300 each!
Also, it is true about the turning circle, it is not very good on this car - it is the P11e (1999 to 2002) and you need normally a 4 point turn instead of a 3, but otherwise, a Superb car and I love driving it. PS, I still think the rarer saloon 4 door looks better than the 5 door hatch, if less practical, but the front end could have been done a bit better, not many saloon cars are as nice looking as this short of BMW's.