One of the best "Header" mods is to fit stainless steel studs(not bolts) in the cylinder heads. Inexpensive kits on EBay.
Like this but check correct size first !!!
http://www.ebay.com/itm/New-Replacement-Exhaust-Manifold-Stud-Kit-Stainless-Steel-Header-10-3196-001-/361793626713?hash=item543c94a259:g:APIAAOSwMVdYEPe b&vxp=mtr
and use appropriate threadlocker in the cylinder head and a removable high-heat version for the nuts.
The exhaust flanges benefit from a s/s +Nordlock retrofit if you are in a climate with lots of salt. The triangular flanges have press-fit hardened bolts which rust and are extremely tedious to drill out when they break.
Threaded Mode
