Lower chain tensioner is really easy on that motor, and if you want to do the vanos stage two rebuild (replaces sprockets upperr tensioner and vanos seals) there are a bunch of good DIY writeups online. Right after I bought my m3 the timing chains started to make alot of noise also. I did the lower chain tensioner and a vanos seal replacement, and it sounds like a new motor. If you are handy with a wrench, i would try to pick that up for about 1k. Good luck.
Member #2 of the Boston Green Mafia BMW-CCA #457574
1995 BG M3(sold) 2000 TiAg 4.4l X5(sold)
-2000 F250 V10
-2004 GMC Yukon Denali
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