Does work with the new driver, but be aware: there are two PCI-PCIe bridges.
After having a disastrous experience with reverse bridging of AHCI controller on G4 (with a common bridge found on eBay), same thing applies with forward bridging.
The cheap $10-$25 bridge boards use ASMedia 1083 bridge. That bridge is know to be faulty, so the manufacturer can buy it very cheap - and make a very cheap, faulty product. There is still a profit even if it is sold at $10. Check it on eBay!
None of them, be it PCIe -> PCI or PCI -> PCI-e does work.
The PCIe -> PCI "produces" a MacsBug screen on "9" and instant kernel panic (once you address the bridge) under every version of macOS-X.
(Chose, what do you like more!).
The PCI -> PCIe will make you feel, it works... for few minutes. The problem is that ASMedia 1083 will screw up the DMA totally.
This is documented in Linux, but I am not going do fix the PCIe driver on macOS for a bridge, which made people like Tejun or Linus mad on their life.
Luckily, the products sold under Startech name DO WORK.
I tried both bridges, so far it looks good.
Did see SeriTek under Mojave today the first time properly.
The performance was not that great, just acceptable (for 3112). 3114 is not acceptable in any form, wonder, why SImage made it - but it's going to be supported, just make sure, your expectations aren't higher, than ca. 63 MB/Sec - while 3112 is clearly over 100 MB/Sec.
I think, we need to demand a good solution from manufacturers without bridges known to be bad.