Converting and Editing AVCHD

[akosvfr]

Hello everyone!
I just registered but i have been helped by videohelp for quite long. Here is my problem:
I want to convert .mts 1080p files from Sony Camcorder, edit them, merge them and make a dvd out of them.
I first tried Ripbot because i have used it in the past to convert .m2ts and it gave outstanding quality, but in this case it does not recognise the audio... So i converted them to .mpg 720x576 PAL DVD with Free HD Converter but the quality doesn't impress me. Specifically too much noise in the picture! I now want to cut some scenes and denoise/clean the video a little bit. Which program should i use? I'm thinking in the end to use ConvertXtoDVD to make the DVD. Is this the right choice? Also should i use something else to convert the original .mts again or edit them directly, merge them and then convert them to dvd with ConvertXtoDVD as it can handle .mts? My goal is to get the best dvd quality. Sorry for the long message, but i didn't know how else to describe accurately the situation.
Thanks in advance!