Just did it last year, but mainly because my winches got stolen.
I fitted Lewmar Evo winches, as the electric version was a lot cheaper than the Harken ones. No idea what winches you have so can't comment on specifics.
I had to drill a 65mm diameter hole in the deck, which was about 25mm thich grp, then with an 8mm aluminium plate, and then a further 6mm of grp. You will need a diamond cutter, and you will also need to chain-drill through the aluminium.
It's important to measure, measure, and measure again before cutting the hole. The motor/gearbox unit sits in the aft cabin above the door. Once you work out how it fits, drill a small pilot hole to check your position before cutting the big hole.
You also need to run 75mm cables in order to take the load.
It's quite a job, and very messy.