There's a lot of free HP bowl porting the heads.
If you cut the exhaust guides for seals, you need to replace the exhaust valves to get rid of the oil step on the stockers. If the seats are recessed, they'll need new seats installed. If the intake seats are recessed, a set of OS Ferras will get you back out to fresh meat.
On the intake gasket, don't use the one that's called for. Get the one that's missing the hole for the EGR port. That way exhaust can't even get to the intake to leak at one of those goofy block off plates.
On your timing chain, I'd go back with a stock set. Granted they're 'shitty plastic covered aluminium, but they last 125,000 miles or 30 years, which ever comes first. While the timing cover is off find the article I wrote with the oil mods and do those for more free upgrades.