That's solid advice. I found myself in a similar spot last year when I whipped up a huge batch of roasted pepper salsa for my cousin in Texas. I decided to pressure can it because I packed it full of onions and peppers. I'm really glad I did, it held up perfectly during the trip and tasted just as fresh months later. If you're mostly using tomatoes and increasing the acidity, a water bath canning should be fine. But for salsas with a mix of ingredients, I'd recommend playing it safe and going with pressure canning too.