The rear sway bar and spacers will both help, but increasing the rear spring rate is also usually a big help. It can be done with helpers, airbags, Sumosprings, etc. The shocks used should also be higher rate than stock. Many use Bilstein as they are high rate, but also comfortable on small bumps.
The bar and spacers may get it to where you are comfortable with it, as handling is a very subjective thing. Or they may not