Bow thruster was no problem. Stern thruster was the worst project ever. I removed the brackets that hold down the aux fuel cell from the front and right side - no big issue. Transfer all of the fuel to the primary tank. What you may not know if there is a third brack at the back of the aux fuel tank, so you'll need to shimmy in between the port bulkhead and the tank and bend into a pretzel to loosen and remove the rear bracket.
Once this is done, you can slide the aux fuel tank and few inches to the left and squeeze yourself in there. There 6mm rachet is available online, as are the shear pins, but make sure you are ordering them for a SidePower SE40 - get several of them.
I placed a block under the thruster when I finally was able to wedge myself in there to support the thruster when the bolt came free (there are only two holding it into the transom, but they are fairly long). Once you remove them, the thruster will hang free as it is still connected to the power and control cables. I got this far only to find out the shear pin was not, in fact, broken, but the thruster was half full of water! It just got replaced, but I finally relented and let the pros take care of that part, as I didn't want to address the rewiring, which likely would have been easy.
There are special pliers that can be purchased to remove the shear pin ring lock, but I simply used two sets of needle nose pliers to pull it off the bow thruster when we needed to replace that shear pin - not too hard.
Hope if all goes well for you! Good luck.
