I have never had any issues with Fel Pro and 3800's... I have used Fel Pro on the 88-91 Vin C, 91-95 Vin L as well... I have never had any of them leak...
I am very picky tho... when I get them torn down the surfaces are as clean as humanly possible... My last step is a good cloth and brake cleaner or acetone... after that I lay a couple dabs of Gray or Black Permatex sealant at the corners of the head/block.... I then apply a small amount on the bottom of the seal and set it in place, then I do the dabs at the corners again, set the intake gaskets in place and add my dabs yet again, then a small bead across the top the the end seals... Then I carefully set the lower intake manifold into place... I have yet to see one degrade so this is interesting...
As far as gaskets go... For the L27 1991-1995 Felpro is the way to go... I have never known these to have any issues in terms of quality... There are a couple other gaskets makers out there ROL is one of them, the Other being Victor Reinz( spelling ) any of those should be fine...
For the later 3800's( Series II and later ) I would recommend the GM aluminum gaskets, Felpro Metal Framed right behind those...