I just did the valve stem seals & coolant pipe and the job wasn't too bad. While at it, I can attest to the fact that every seal & gasket was shot at 145,000 Km (a little less below 100k miles). So if I were you (OP), I would go ahead and take my time and do job myself, and change every seal and gasket, from VCG, to upper timing gaskets, intake manifold gasket, all O-rings etc. If you do only the one VCG, you will leave many potentially leak points exposed to near future failure. Guaranteed. Again, this is from personal experience, and your vehicle might not exhibit the failure of all gaskets and seals. The cost of parts is not much. If you intend to do the valve stem seals, then you need to buy the AGA tool, which is not cheap (or rent it if anyone will do so).
First time I did the job, it was a bit overwhelming, but then I had to take off the VCG's, due to an error, and the 2nd time removing the VCG's and re-installing them,I found the job actually quite easy.
I believe it's much harder and more involving to replace the engine, which might have the same cr*ppy OE parts that will fail, only to be back to square 1 again, any time after 60k miles.

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Stable: e92is, e46 M54B25, e83 N52, e53 N62 - sold, e39 M54B30 R.I.P.