The STX is a bargain for what you pay but the difference between the SX and the STX is in the Titanium Worm Shaft, Spool and other refinements. I personally wouldn't buy the STX if you're taking it to the places you already Bass fish Softie. It would be the Revo INSHORE for me, all the way. You know how the braid and spool can get so wet whilst in use regardless, the thought of it all swishing around in a non SW reel doesn't appeal to me.
If you want to use lighter lures with a baitcaster then you need a more forgiving rod than I have. It's the acceleration that you impart in the lure to make it fly which causes birdsnests (does with me anyway) and I used Vidars Inshore on his Lamiglass rod which is much softer in the tip. Worked a treat and would work fine with 7gr lures, not so sure any baitcasting reel no matter how much you spend would cast little lures well without a huge amount of practice on a stiff, short rod. Sure you can make a 7gr lure plop 20 yards regardless but that's not what you always want. I can however chuck a Zonk/TN60/Combat Crank miles (figuratively) with my SX with no problems all day.
As Vidar always reminds me, think of the package as a whole, not one component, as unless they are all correct you won't achieve the results you crave.