The ZS10 is going to be the best value for money IEM you can get for bass - as noted in the thread early, if gives you loads of headroom in the lowend and whilst it doesn't have the most honest of signature or wide soundstage, it does serve as a great on stage monitor. Certainly for less than 40 quid, you'll be hard pressed to find a more performant monitor - in fact, they'll smoke most 400 pound monitors. I wouldn't bother going anywhere else unless you are ready to get into the world of customs, where you are looking at something like a quad balanced armature IEM or the oddball UE6 which gives you good performance and headroom, whilst retaining a lower pricetag due to it's hybrid driver setup.