Clips in same format as the original?

What program should one use if the only thing one would like to do is split and join movieclips simply?
I would like the output files always to be identical copies of the splitted portions of the originals. And this analyzing and copying the format if possibly should be done by the program itself and not by me (format, frame rate, compression, bit rate, audio etc ie every single value duplicate to the original). I have tried Windows Movie Maker, there i have not been able to split mpeg movies and output in mpeg, the quality seems to go down when trying their formats. And one more, selection of splits I would rather do by inputting the start and stop times than messing with the mouse. So is there anything out there for me?

Try DVDLab if you want them output to a dvd format or try TMPGEnc if you just want to join mpegs together.
Your message is a bit garbled what exactly are you trying to achieve and we might be able to help you better, ie do you want these mpeg files for just the PC or to put on a VCD or a DVD etc etc etc…