Its a great upgrade after using Sundara for a long time. Sundara is a great headphone but it lacks strong bass unfortunately. So after searching for planar magnetics with strong bass I ended up with HE6se V2 and decided to try it. I am so glad I did. This headphone is like a F1 Race car that is limited not to pass 90kms/hr.To break that limit it needs an EQ. First I used it with my SMSL M500 MKIII Dac/Amp and I was disappointed. Then I bought Singxer SA1 headphone Amp to boost its performance. The sound level increased like 30-35 percent but it was still a bit bright with the heights and lacking bass. Then I decided to try EQ and installed Peace and select Bass Boost. OMG ! It got rid of that slight bright heights and added the bass I was looking for all that time. It started to sound just I was expecting it to sound right out of the box. Also the sound is more clean and clear and detailed than Sundara. Its just amazing!So basically to get the phenomenal sound from this headphone:1.Just EQ it with your current Dac/Amp. If the sound and bass is loud enough for you, you may get away paying an extra money for a new Amp.2.After EQ if you think the bass is still lacking or the sound is at max but still not loud enough!Then you need to look for an good amp something like Topping D90 or Singxer SA1 etc.. ( I am using Singxer SA1 with volume knob always fixed at around %85-90 and from computer at %50-60 usually. When I want louder I go %70-80 from computer but never passed %90.(without jumper mod which makes SA1 even louder). If you have the budget you can go for higher Amp of course but not necessary if you ask me. ( I saw a lot of positive comments in forums about Soloist 3X with HE6se ). If you don't have the budged there are some people saying they get very good performance with some cheap speaker amps but never tried so I cant comment on that.About the Headband Mode ( Do You Need it?)If you find clamping force is not enough and top of your head starts to hurt after half an hour or less then the answer is YES (which was my case).If you are fine with default headband congrats you just saved some money. There are different headband mods for this headphone across the web but I think Hifiman Hybrid headband is one of the best and it is very simple also (Its taking 3-4 min to change them). Search for Hifimen hybrid headband ( which is Sundara headband ironically :) The trick here is you need to use the original 4 screws that is coming with HE6se not the ones which are coming with Hifimen hybrid headband !About the Grill Mode ( Do You Need it?)Some people say it increases sound stage a bit because it is more open but honestly It is very minimal difference and very difficult to notice. There are lots of grill mods again. But I bought mines from arcticcables because they are CNC cut and they look and fit much better. ( For dust filter I bought 2xpack 120mm dust filter Ultra-fine Mesh for computer from Amazon. I cut and glued them they looked fabulous. The trick here is just don't use too much glue only edges and a bit in the middle otherwise they look terrible)DOES IT WORTH THAT MUCH HASSLE FOR THIS HEADPHONE?DEFINITELY YES !!!