I'm generally not real big on modding and accessorizing stuff like a lot of people are, and agree the Sport is pretty much GTG, as is.
But, along with that grip change, I would consider a Magpul handguard set. They're pretty damned cheap, but are highly functional and ergonomic, versus that unconfortable little waffle thing they come with.
If you handle a rifle with one on it, I'm sure you'll "get it" immediately.
One other thing I would recommned, probably even more than the Magpul handguards, is the Tapco Intrafuse T6 rubber buttpad. It folds around the plastic butt on your factory stock, and adds to the length-of-pull, as well as increasing the overall surface area.
These things make shouldering the original stock surprisingly more comfortable, the difference is night and day. They're cheap, I got one on ebay for something like $10 delivered, but they're really worth it.
Take a look.......
TAPCO T6 Recoil Pad Rubber Black 1