Changing adapter and adress (external network)

Dear folks,

first of all, thank you for helping me as a new user!

I am using the free home edition of the UTM. I am absolutely happy with as it does its job well. It runs behind a fritzbox 7490 (the fritzbox dials-in to a VDSL network) with a port forwarding of required ports to the UTM IP. 

Setup:

FritzBox 7490: WLAN-Mesh with second 7490, no DHCP

UTM: DHCP with PAC file to auto-configure all hosts

all devices in one network 192.168.2.0 (not the best solution security wise, I know.)

Issue #1

My internet connection will exceed 100mbits in a couple of weeks and I need to change the 10/100 ethernet adapter in my UTM box for a 100/1000. 

Issue #2

I was given a company laptop on which I don't have admin access. I need it to bypass my UTM.

At first, do you expect trouble with changing the network adapter or does this work seamless? Secondly, does changing the network adress of the external adapter work seamless?

target configuration:

Fritzbox 7490 with netowork 192.168.2.0, active DHCP, Access Point for Network 192.168.2.0 (for company laptop with VPN/IPSec)

UTM with external IP 192.168.2.x, internal network 192.168.3.0 with DHCP + PAC, Access Points acordingly for all private devices

Any hints welcome!

Thank you very much!

Torsten