I did that job on my old Cobra drive this past spring, the tough part is getting those caps off, if you can do that, the rest of the job is pretty easy. BRP still sells the seal kit for the Cobra drives, it could even be the same thing for the outboards but I don't know for sure. I had a spare set of freshwater used trim rams so I took those apart, left my old cylinders on the transom mount (so I didn't have to disturb the hydraulic fittings) and used the rams from the freshwater units, my old ones were getting pitted. Believe it or not the original rams lasted about 35 years before leaking, just a little! I used a bit of heat on the end of the cylinders and had to put my full weight/strength into using that pin wrench to get those caps to move....
To do each side the seal kits were $55 each, I forgot what I paid for those used trim cyls but you can buy them for Cobras in good shape for like $150 or so.
First see if you can get the seal kit for your model #, then check the ram to see if it's pitted or not, you can probably find those used if it's pitted, next you have to have at it with the pin wrench. GOOD LUCK, getting the caps off is not easy!