For the 3.1 ROM installation, you'll have to check the revision number of your motherboard (printed on board at bottom right corner).
If you have Rev. 3 or Rev. 5 (like I have), you'll have to bend up pin 31 on the ROM (so that it won't enter the ROM slot) and solder a wire from this to pin 21 on the ROM. Then solder a wire from pin 1 and plug the other end of this wire into the pin 31 slot.
When removing chips, be very careful because it is extremely easy to break or bend the pins (and if they are bent too far, they will break when you try to bend them back). The Agnus removal is easy if you've got the PLCC puller like Patrik mentioned - and there are thankfully no pins to break on that. It is stuck in there pretty hard though.
