I have not done this job, but I seem to recall posts that claimed you could do the job without separating the inner & outer intake manifold sections that are joined by the rubber sleeves with the Oetiker clamps.

However, it would seem that you would want to be quite sure that neither the sleeves nor the clamp joints were the source of the leak(s).

I seem to recall the basic procedure being:

1. Remove injector rail, injectors, rubber donut seals in the intake manifold. Note that if you're not fairly gentle in removing the injector rail, you my cause it to develop a leaky end cap. I have experienced this personally.

2. Remove bolt or nut at the bottom mount of the intake plenum chamber.

3. Remove flange screws at top on inner intake manifold section at joint w/ head.

4. Loosen, but don't remove flange screws at bottom on inner intake manifold section at joint w/ head. Bottom 'holes' are slots in intake manifold.

5. Entire plenum/intake manifold assy can be raised up just enough to get the inner intake section free of the lower flange screws.

I think that's the basic idea.