This is a killer price. I just had my valves cleaned about 10k ago though. I'd recommend this to anyone that has an N54 and hasn't got it done within the last 35-40k miles. I've been running meth almost the entire life of my car and my valves still looked like absolute crap after 50k.
You should do this whether you are stock or modded if you are anywhere near 50k miles and haven't had it done before.
Legal Disclaimer: Anything I or anyone else says about my vehicle on this website(e90post.com or any affiliated or nonaffiliated sites), pertaining to modifications, is only to gain acceptance from my/our peers, and does not actually represent anything actually existing on my car, and thus, cannot be held against me in any issues, i.e. warranty claims, that may arise.