ReplayGain BEFORE encoding as MP3? Options

[BFG]

I've read elsewhere on these forums that applying ReplayGain or AlbumGain BEFORE encoding a lossless file as MP3 can slightly decrease the size of the MP3, and increase the overall quality - assuming that the dB level is reduced - because LAME then places less focus on retaining the now-quieter background noise.

I'm looking for a quick and effective way to achieve this from a technical perspective. I'm currently ripping my entire CD collection as FLACs via EAC, and need suggestions on how to encode the same collection as MP3s that have AlbumGain applied before the transcode step, without losing any metatags or album art. I'd prefer also to be able to split apart two-song tracks (i.e. end-of-album tracks with "hidden songs", or pregap tracks) into separate MP3s.