3.8 intake manifold leak

I have an intake manifold leak(coolant) on both sides below the throttle body on my ’97 lesabre and I have read that this is a common problem in this forum. My question is
1) has anybody try fixing it with the Ken-co product ( epoxy intake and adding spacer for EGR passage) and did it work and for how long?
2) And did anybody try buying the aftermarket intake manifold and did this work?
3) Also would it be better to install the after-market intake and the Ken-co product to give it a double protection.
4) Is replace with Dealer part (intake manifold) fix this for good or will it come back later.
5) Any comments? Sorry for all the long questions and thank you all for the response.