When I want to change from an "e1000" or other I just modify the ethernet(n).virtualDev option in the .vmx configuration file while the VM is shutdown, not suspended.
Example
Change:
ethernet0.virtualDev = "e1000"
To:
ethernet0.virtualDev = "vmxnet3"
No need to muck with IP Address, etc.
As far as doing it with VIX I don't have time to look at it, sorry.