That's really all you need to know.
None of the stuff about heat, such as it is, should really be the primary consideration for an explorer.
It's all about weight.
EVERY drive mod' either increases power consumption and, thus, requires a better PP, or it increases weight directly.
Simplest choice is to not bother modding thrusters at all.
IIRC, my AspX explorer is running a 2A PP and 4D thrusters to minimise weight and modding the thrusters would require a bigger PP and put a noticeable dent in the jump-range.
Pretty much this ^
I went with the option of simply not bothering because the percieved gains simply arent enough to justify the time spent doing it in the first place...unless of course ye enjoy spending time in the bubble as an explorer which I dont personally, and make sure I spend as little time as humanly possible in it. Which is another way of saying I literally couldnt be bothered with the engineers at all, although to be fair I do have other modifications on other modules...all low level grade 3 stuff which I already had.
The thrusters however...as an explorer, the only reason I have a thruster fitted at all is because I have to have one so its the lightest thruster one can find that can actually work on the ship...fer me that was a compromise of sorts as the ship is a type 9 and heat management is a fairly major concern fer me as it is. Fer any exploration ship with a sub 20ly range, saving a few grams on thrusters really does make an impact. As such, modding them is sorta pointless because there are no real benefits if it doesnt cut weight. Thats from the perspective of setting up a ship fer range without using the engineers to put one of their voodoo spells on the fsd to offset any setup compromises entirely. So while it is very easy to ignore engineers entirely, the reality is it wont make life any easier by doing so but then some of us get off on impossible challenges...like flying sidewinders to BP just fer kicks.
Ok so technically there are some benefits, but from my point of view which is subjective at best, they just werent worth the hassle. I see it like I used to see full suspension bikes over hardtail bikes...it allowed one to make mistakes and ride faster and still be less skilled than the hardtail rider. An old mountain biking analogy which actually makes a lotta sense when ye think about it ^