I've head bad things about cometic head gaskets and bleading between the cylinders etc...

As for the actual build...

Use arp bolts / studs etc
Pistons / Rods depend on boost
Bearings I've had good experience with King
Headgasket / never had issues with the standard one
(h/g should only be blown if something is wrong best blowing a gasket than warping your head)

Though the most important aspect of this build is the tune. No point having all the good bits and a dodgey tune as it won't last long.