No it's actually very simple.
The plastic manifold is sealed with an o-ring style system.other than the egr pipe the manifold is easy to loosen and reseal.It is not very common for the manifold to leak unless it has alot of miles or it has been over heated.On a 98 SOHC it should have a split manifold,You need to check to see if it is leaking between the upper and lower halfs or is it leeking between the base and the cylinderhead.If it is the base to cylhd you just need a 8 or maybe a 10mm socket and extension(some times guys have changed the bolts)for the base manifold bolts and remove the egr pipe asy from the manifold,(should only be one screw for the retainer that is also sealed with an o-ring)loosen the clamp for the flexable bellow to the throttle and gently slide the ducting free of the throttle.lift the manifold and pull ou the o-rings from the molded grooves and replace with new ones(making sure to seat them into the manifold as they will stay in place by themselves).then reassemble.If it is between the base and the upper half the opperation is the same eccept you dont have to remove the base bolts,you have to remove the screws that hold the two halfes together.They have a t-30 torx head on them(they are like long wood screws)the seal between them is like a molded strand of o-rings.Seperate the two halves and exchange the old for the new,them reassyemble.
Boda bing boda boom.
