I'm looking for clarification on a topic that seems to have varying opinions in the realm of string mixing: the use of a heavier E string with a mittel - or even weich - tensioned set. There seem to be three general schools of thought on the topic that I've discovered so far. 1) For - A heavier E string is good to experiment with if one is looking for more 'oomph' or power in the low end. I've seen many examples of this on here in my reading, be it (but certainly not limited to): a Stark Spiro E with mittel A-D-G a Mittle Spiro E with weich A-D-G a Stark Spiro E with dominant A-D-G. Swapping the E in a set of flexocors for the next gauge up. One recent poster on the Evah megathread indicated that he was using Evah Weichs with a Spiro Stark E. Now that's a big tension difference. 2) Against - I hear opinions of "Bass string sets are matched for a reason and as a result shouldn't be messed with." Many have reported on here that they've experimented with swapping Es on a set they didn't quite jibe with, only to return to the original E of that set for various reasons. 3) Against - the uneven tension of a heavy E with mittel or weich upper strings is dangerous for the health of the bass. Points one or two are well into the realm of personal opinion. As much as I appreciate the wise disclaimer of 'YMMV' when it comes to the tonal properties of strings on different basses, I am hoping for a little bit more of a scientific perspective in regards to point number 3. Take just about any well constructed bass. What are the inherent dangers of throwing a Spiro Stark E under mittels or dominants, or strings of equivalent tensions? I'm really hoping to hear some comments or stories from those with some experience with these matters.