I replaced the stock radio on my '97 Sonoma before I bought my Blazer. I just bought an installation kit from Best Buy or something and it wasn't too hard from that. Just remove the Bezel with the two bolts above the cluster and it pulls right out. As far as another power source, the battery would be the best source although I beleive it would be ok to the connect to the starter cable (which connects directly to the battery as it is). However I am sure there are many electronic experts out there that know more than I do.