Will LAME's lowpass be more "safe" (quality-wise) than, say, a lowpass in Cool Edit?

I'm about to encode a large amount of stereo FM radio tape recordings. I thought running a 15 kHz lowpass to start with would improve the results of a subsequent noise reduction, but since some features in Cool Edit seem to affect the quality more than others, I'm a bit hesitant to process the sound more than necessary.

So, are there any notable side effects of the lowpass function in Cool Edit? If so, I might just refrain from any Cool Edit processing at all, and just let LAME do a lowpass.

A lowpass using CEP's FFT filter with a 512 point FFT and a Blackman-Harris window is very good quality and just fine for what you want. But in order not to lose a little bit of resolution, the right way to do it would be to convert the wave to 32 bit before lowpassing, then lowpass, then save to 24 bit, and then compress. You can do this to all your files at once using CEP scripts & bacth processing.

LAME filterbank lowpass filters are only slightly worse than CEP with the settings proposed, and I don't think the difference would be audible (you could test for yourself), so I doubt it is worth the extra effort of manually lowpassing before encoding. So you decide

Thanks, KikeG!