I just bought one a week or so ago, and out of the box I had the heat problems too. Overheat while leaving planets, overheat charging the FSD, and scooping was borderline right out. For me, it just had to be fixed.
Putting the Thermal Vent experimental on the power plant and FSD seems to have fixed it, for the most part. Yeah, it kinda sucked to lose out on the range increasing FSD experimentals, but I can get off planets with ease, charge up jumps, and even run the scoop without incident. All while maintaining my G5 7A dirty drives, a full G6 reinforced shield, and 36.97 LY max jump range with 12 limpets in the cargo hold! It might be worth noting that I also downgraded the fuel tank to a 64T. You notice that you actually have to scoop instead of just ignore stars on 2-300 ly journeys, but it adds a bit of range and makes it more manageable to top it off.
The one thing that holds it back from being a rock star explorer is the lack of a size 7 module slot, in my opinion. If you could put a grade 7 scoop on this thing, it'd really travel well. As is, that's the one drawback I'm really wishing I had(and enough module space for a fighter, shield, AND scoop of proper size for the ship, but that's another story).