A few answers...I have a 330ci and have driven all the M3's (e30/e36/e46) so medyo may comparison ako. First of all, kung kaya mong bumili ng e46 M3, you can get a new Boxster...they are very similarly priced. The 330 is $35k base, but with all the desirable options (leather, sunroof etc) is more like $40k. The 330 is a great car for the money and performs/feels very much like the e46 M3...the M3 is much much faster but doesn't feel that way (smooth kasi ng power delivery eh)
The e36 M3 is a wonderful, wonderful car - I cannot praise it enough. Although BMW has high maintenance costs and might be an issue if you're buying a 6 year old car (especially sa US where labor is not cheap)...the s/c is not really an issue reliability wise since it's low pressure and the S50 engines are built really tough.