I have Banks headers on my V-10, installed the supplied gaskets with no additional sealant and have never retorqued the bolts. That was 5 years ago and the EX is used almost exclusively to tow the 11,000lb travel trailer, so it sees plenty of heat and RPMs, no leaks yet.
I agree that even shorty headers will be an improvement over the super restrictive stock manifolds. When I did my install I took the measurements and the interior cross sectional area of the stock manifold just after the 5th inlet port is only 20% larger than EACH of the Banks primary tubes. The addition of headers improved throttle response and the freer flow really makes nice gains at higher throttle openings under high load like pulling long steep highway grades with the big TT on the hitch.