I did this earlier this summer on my 2001 3.0i. Fun project. You can search for my posts / threads on that. Glad I did it myself, but I can see that it might not be a good idea for everyone.

youtube 50sKid has a great series of about 30 20-40 minute videos on the full process, including bottom end. But he does the job so you can just skip the part regarding the bottom end. GREAT videos. Realistic, not sugar coating anything. He goes through the tools required, budget, etc.

So I'd recommend to watch a few hours of those videos and decide whether you are up for it.

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2001 X5 3.0i, 203k miles, AT, owned since 2014