I did mine about 3+ years ago and the worst was the 'spring'! You can read about some of my toils in MENU#24.
You do not have to remove the intake manifold, the ETA can be removed as shown in the instructions! Suggest you don't remove the spring but keep it anchored into the manifold but just tape it out of the way. It's tough to get it back in. For the gasket, you could use a little gasket material to ensure that it doesn't move as you attach the four bolts.
Don't forget to clean the old gasket off after removing the old ETA.
It took me about 3+hours to do it and the worst part was the 'spring' b/c it fell off; about 1hr to get it back in!
Russ, tnx for the pictures; added them to MENU#24.
