alright so I think I figured something out. I was trying both my Explorer and Performer 5+2 with the Spinfit W1s. I was reading up on
this site, where they compare different Spinfit tips. They have this to say for the W1:
SpinFit W1 – a combination of the cap shape which is in between of Omni and CP100 and a bit softer silicone material allowed a deeper insertion that results in extra sub-bass rumble with a bit more relaxed mid-bass, balanced natural mids, and extra sparkle in treble.
So that description sounds great for the Explorer, which could use a little more sparkle in the treble, but I'm afraid that for the P5+2, it's accentuating the treble a little too much to where it could be fatiguing. I really like Spinfit, so I've ordered the Omni and the CP100 to see if I get different results.
Highly recommend the W1 with the Explorer though.