I have had several installs at geek squad involving subwoofers and when they tune the amp they use their ears. Best buy does not provide them with an o-scope or specialized tuner. If your lucky, you can find a tech there that has their own o-scope or voltmeter to do the tuning, but I've only encountered that once with a tech that has a master certification and he was really into car audio. I don't know where he went but where I go to do installs he is no longer there. Subwoofer install covers putting sub in box, that's it. The amp install is the main thing and it can be from $70-$125 depending on type of amp.