I'm not using redtop exhaust manifolds, I'm using RWD exhaust manifolds. Two rather completely designs. Of course, I'm only going by what I've been told, so I could well be wrong.
Extractors, exhaust and pod are obvious first starts to mods, but only if that's where the problem is to start. I was told the extractors were fine, so I got the exhaust and pod.
And no, I've found about 4 different kinds of aftermarket extractors for RWD 4AGE engines, and I've never found a set that would fit in a KE35. 3 of those sets fit in the actual engine bay, but none would clear the idler arm properly. If you run a jap bellhousing (like Rollie did) then you can heat and bend the extractors to *just* clear the idler arm and fry your starter motor instead, but I'm running an oz bellhousing.