What parts are needed

You need a complete ring and gear set and an installation kit. If they make a solid pinion spacer to replace the crush sleeve I'd put one in. Makes the setup easier IMO and if you ever need to take off the yoke it doesn't disturb the pinion bearing's preload setting. I have never done a 8.25" rebuild and gear change but have read several times the carrier that came with the 2.45 gears can only be used with 2.45 gears so you'll need a new carrier. Depending on how many miles are on it you might consider changing all the bearings also.