For my 68000 Amigas using Cloanto's Amiga Explorer I replaced the serial.device with BaudBandit.device to be able to run @38400kbps.
On the A600 I'm using a Whippet, on the desktop A1200 an internal Port Plus Junior or a PCMCIA NIC or wifi.
On A2000 a PC bridgeboard and an ancient 3COM ISA Ethernet.
On the 1200T just the PCI ethernet. 
How well does that work with the ISA Ethernet in the A2000? I have a 286 Bridgeboard in my A2000... Are there any specific requirements for the ISA Ethernet card? Can you access PC drives from the Amiga, and visa versa? Can you get online with the Amiga?
I have a GVP 040 in my A2000, and it has a high speed serial port on it, so I'm using Amiga Exlorer at 115,200 right now. It's not horribly painful at that speed. But it's still too slow, and I don't like the fact that I can't access the PC drives from the Amiga.
I haven't tried connecting my A1200. I would love to get one of my Miggy's online...
