Moving the ECU

Alright it looks like I'm gonna put in custom seats to give myself more head room. The problem is the ECU is located right under the drivers seat, taking up a couple of inches. I guess I'll just mount it on the floor behind the drivers seat. My questions are;
1. How difficult of an operation is this?
2. Should I have it done professionally, or is this a DIY project (the seats seem to be)?
3. Does someone make a wiring harness that goes to the ECU longer or an extension or does it need to be fabricated?
Thanks.
1. How difficult of an operation is this?
2. Should I have it done professionally, or is this a DIY project (the seats seem to be)?
3. Does someone make a wiring harness that goes to the ECU longer or an extension or does it need to be fabricated?
Thanks.