I was new to this car and when my 90's injectors failed with the ethanol. If I had a garage that I could work in I would have left off a few items from the shopping list. If you own your garage then I would consider leaving the injectors & coils & wires as you say that they pass muster now. Besides now that you see that the plenum pull is really just a lot of detail work, the next time it will go so fast that you will be amazed.
Obviously the other side of that coin is when will the old stuff fail? In the middle of the summer when we are using our cars? That's when my stuff quit & it stunk as far as I was concerned; plus I had to wait for restocking on some stuff.
With the advent of Accel injectors & their price, I would consider doing the r&r now....they are sooo much less than the other alternatives....but that is a call decided by the budget at hand.
JMHO
Tom