So, I've been out of the setting for a spell, getting my Eclipse Phase on, and thanks to Shadowrun: Hong Kong, I'm seriously considering running another SR4 game.

I got out around the time SR5 came in, because I looked at the shit-show SR5 was turning out to be, said "ahhhhh frag that," and made the jump to full-on space transhumanism. I still love full-on space transhumanism, but I'm kind of feeling some longing for the Sixth World.

I also noticed, checking my SR4 Chummer (autoupdates FTW,) that Gun Heaven 3 had stuff for SR4, but when I looked, Gun Heaven 3 was an SR5 branded book... So...

Did a lot of that go on? Which SR5 books, besides Gun Heaven 3, have SR4-relevant crunch, if any?

Look at http://rpggeek.com/rpg/21069/shadowrun-5th-edition and see which books are marked for both SR5 and SR4:

Aetherology
Battle of Manhattan
Bullets & Bandages
Character Conversion Guide
Firing Line
Gun Heaven 3
London Falling
Sail Away, Sweet Sister
Shadowrun: Gun H(e)aven 3 Weapon Cards
Sprawl Wilds
The Vladivostok Gauntlet

Nitpick: the Gun H(e)aven 3 Cards are actually two separate products. One has SR4 stats and the other has SR5 stats. Everything else is a single product that contains dual-stats.

But yeah, Larsine nailed it.

If you care, the same information can also be found in the Shadowrun Product list in my sig.

With the direction Chrome Flesh is heading, you can now get both at the same time