I did the 996 cluster and it was indeed a drop and play. No issues at all. I am guessing that the '03/'04 Boxster ones will be the same for your '01. Because we don't have the newer radios that is not an issue either. Just make sure that the plug colors on the one you put in match the ones that are on yours. IIRC they are Green blue an gray on ours. Also, with the '03 and '04 I think you want one that came with the OBC function to get the Dot matrix display in the middle.
Here is an '04 cluster that qualityporscheparts is selling. It did have the OBC function.
04 Boxster s rwd Porsche 986 Gauge Instrument Cluster 98664123302 Silver 147 879 | eBay
I had odo-pro reset the odometer on the 996 cluster I put in. Easy mod.