1. Load your M2V into VirtualDubMod/VirtualDubMPEG-2 and save out an AVI using huffyuv (lossless) compression, then edit that AVI. Need a lot of hard disk space.
2. Get AVISynth, DGMPGDec package and the AVISynth Premier plugin. Free software but some people have had problems with this method.
3. Buy the Mainconcept MPEG plugin for Premiere.
Look back through the previous threads for more info.