You can’t mix Boom with aftermarket. You would have to get an amp and 4 speakers if you want to do fairing and lowers and a few other bits. There are a lot of happy Soundz customers but I personally would not pay what they want for it.
I have Soundz Customz systems in both my bikes. I like them a lot. They are expensive but I like the sound, the ease of install, their warranty, and great customer service. Maddy and Pete are great to work with. That being said there are a lot of killer systems out there. Some more expensive some much less costly. I also think it’s tough to get any two people to agree on what sounds good. So I guess it comes down to how each person wants to spend their money. My best advice would be try to hear as many different systems as you can before you spend your cash.