As I'm obsessed with M42 I thought it should be the 'first light' target for my newly modded 450D. I removed the 'IR cut' filter and installed a 'Coldfinger' cooling system. The sensor ran at 35 degrees all night, considering ambient was 28 degrees I think it needs some work.
I was battling clouds too, from twilight until Orion peaked over the trees to my north the sky was perfectly clear, then some high altitude wisps appeared followed by a fairly solid march of thick patchy cloud. So after I threw out all the subs that were smeared because I still haven't gotten the auto guider hooked up (no fault of the autoguider, I'm still working on the guide scope), and threw out all the subs ruined by cloud I was left with about 15 minutes worth of data.
To say I'm impressed with the difference is an understatement. With 15 minutes data from the modded 450D I have an image that is far more detailed than the hour's worth of a data I collected with my unmodified 550D. Considering I was imaging at ISO 6400 on the 550D and only ISO1600 on the 450D, and for a quarter of the time I'm amazed I got the final image that I did!