A shop in Canada (Vancouver) was having an “open box” sale on HiFiman headphones. There was a transportation problem and he ended up giving me a new set for the same price.
I got a set of Fostex TH-610’s from them a few months ago during an open-box sale for about the same price.
It will be interesting to see what kind of sales happen next month as most companies must be hurting hard, unless they are an online business.
if you ever hear about a deal like that on 610’s again you’ll have to let me know 
I just check this page out every week or two.
https://headphonebar.com/collections/open-box-deals
I had this exact poster question last week as I was deciding on either the Sundara would be a good fit for me or not.
In short, you can buy them without worry. They are very neutral. But if you still want some additional bass its easy to improve with an EQ or an amp that makes them a bit warmer.
I’ll cut it short. This is my first post. I got the Sundara’s yesterday and these are my first audiophile grade headphones. Before them my main headphones were the gaming headset Astro A50.
So if a beginner like me that for years listened to music filled with bass all over it is enjoying the Sundara you probably won’t have issues.
But still, if out of the box you want a bit more bass do what I did.
Either use an EQ to pump the bass a bit or use an amp that is a bit warmer. I only have portable amps (i’m just starting after all) and in my case I got the “ifi hip-dac” and man. It’s exactly like Z said in the review. It gives you great bass without killing all the detail.