I am using the batch encoder in dbpoweramp, what are the differences in the three forced profiles in the Nero M4a encoder,

Force LC AAC
Force HE AAC
Force HE V2

and when would you use these. I just encoded 54gigs of Wavpaks with no forced profile, and they sound great to me, although a little on the large size, setting used was q.55 VBR. Should I have used one of the forced profiles instead. My primary use is to load up my 160gb ipod, and run it through my receiver to my polk speakers, and also grab the ipod to go.

It is better not to force any profile with Nero's AAC encoder. Let the encoder decide which profile to use. Nero's AAC encoder will determine which profile it should use based on the bitrate you are encoding. I believe that HE-AAC and HE-AACv2 is used for bitrates below 96kbps. It doesn't matter though given that your iPod cannot properly decode HE-AAC files. You shouldn't worry about HE-AAC especially since you used a VBR profile that is larger than 128kbps.

If using on the iPod, low bitrate encodes could wind up as HE AAC which will not work on the iPod, so forcing LC is preferrable. Though, encoding at q.55 is no problem, as that should be LC by default in almost all cases.

Edit: Spelling