There's no need to pull anything apart to get the ECU out.
Pull the rug back on the passenger side, disconnect the 5 connectors [3 on the ECU and the 2 beside it], remove the 10mm nut for the bracket.
Go to the drivers side, pull back the carpet and remove the 2 10mm nuts for the 2 brackets on that side.
There are also 2 brackets for the wiring that are attached to the ECU. 1 is for the COR [Circuit Opening Relay; for your fuel pump] and one for the 2 wiring harness connectors on the passenger side.
Once all 3 nuts are removed the ECU is still a bit of a PITA to get out because the brackets are tight against the 3 studs.
I've found it easier on occasion to remove 1 or more of the brackets from the ECU. Each is held on by 2 phillips #2 screws. Be careful you don't strip out the phillips heads; it helps if your hands/wrists aren't weak.