ok, if i were you, i would go and buy some gasket goo/kit for $15 odd from supercheap, or whatever's near you. smear some on both sides of the gasket and put back together. i mean its a 15 year old gasket, and when taking it apart can lose the cushiness, if you know what i mean lol.
if you end up doing this, it'll probably say on the instructions, but after you've smeared it on either sides of the gasket, do up the 3 bolts finger tight till it squirts out the edges and let it set for 40-60 mins, then tighten them up but not hulk tight.
i ended up doing away with the old gasket and used the gasket goo, so it does the job as good as the nissan gasket. (one day someone will discover an AAC valve gasket stuck somewhere under the air intake plenum)