Let's get throat hit out of the way first.
There are three primary factors that contribute to throat hit. Composition of the liquid. Wattage at the coil. And to a lesser extent, the nicotine level.
Regarding the liquid's composition. PG = more throat hit, less vapor. VG is the opposite. The cartos you're getting from GS are most likely filled with a 100% PG based liquid.
The wattage at the coil in the atty/carto determines how hot the coil gets. A hotter coil is going to produce hotter vapor, and you will feel that in the back of your throat.
Finally, the higher the nicotine level in the liquid, the more throat hit you're going to get from it. I find that this is a very minimal factor, but others claim otherwise. YMMV.
On to new devices then.
Sounds like maybe you want to explore the world of mods, perhaps bottom feeders specifically since you drive a lot and seem to be a dripper. Bottom fed devices are great for driving, because you can vape with one hand and keep the other on the wheel at all times. By far, the most popular bottom feeder is the REO. They have a huge following. I'd suggest checking the
REO sub forum for more information.
REOS are fairly expensive though. If you want to get your feet wet with a bottom feeder without spending a lot of money to do so,
Old Goat sells bottom feeder box mods for $30.
If bottom feeders aren't doing anything for you, there are tons and tons of different options when it comes to mods. Fixed voltage, variable voltage, small mods, large mods, etc. Trying to recommend something specific would be very difficult without knowing more about your unique preferences. My best suggestion would be to check out the
E-cig Mod Database and see if anything catches your fancy. If you find something you like, search the forum to get more info on it or post up a new thread.