Check out the work they do and if they have pictures check them out as well. Also most installers good and bad have worked at multiple shops so try and find out where they have worked in the past. Once you get that information see if there are any local forums that would have any particular knowledge about the installer in question.
As a final note remember that it is the actual person doing the work, not the shop name he works for. I've seen too many people go to a particular store just because his friend's car was done there in the past. Ignoring the fact that a bad *** installer probably did the work in the past, and now the same "store" has gone through multiple ownership issues, and several different installers.
I actually wrote a piece on this subject many years ago for the Iasca newsletter.
You can not just pick an installer. You have to pick a shop that backs its installer and pays them properly.
1 Certifications do not mean **** unless they are master certified. These are written test and its hard to pass. Not many master certified installers out there. When i took and passed mine there was only 30 in the country but that was years ago. Im sure there are way more now.
2 Look to see how many holes the shop has in its sound board. If they can not afford to stock the store they can not afford to pay the installers very well .
3 Ask how the installers paid . If paid on commission . Turn around and leave instantly.
4. Do not look at trophies and assume they know what they are doing. See what the trophies are for and how old they are. The installers who did the trophy installs could be gone. Or they could be for spl in 1993 .
5 If they have a demo vehicle listen to it and ask who built it. Ask some things that only the bulider would know. Like are the comps run passive or active. Believe it or not . I have built demo vehicles for many shops that i did not work at.
6 Ask to see the installer that would be working on your car and chat with him. Ask him what he has in his car and if he has a system ask to listen to it.
Some great installers can not tune a car to save his or her life.
7 check with other shops for price quotes. just to make sure you are not getting high or low balled.
8 last but not least do not leave your car if you do not feel 100 percent comfortable. Also i would leave a disposable camera if you can not be there and ask for pics of the install while its being done.
I think i could do this myself its just that is 07 still new and i would hate to mess something up.You know i would love to bring it to either of you guys I'm just stuck in the middle of both of you. Thanks for the info going shop around for a shop.