It's interesting to see how STI changes in past 10 years. Despite the fast that they keep the same engine, subaru has been revising the handling year by year. No one said GD STI was a bad handling car right? Subaru didn't take the way as GTR did. I think subaru and Mazda are similar in developing their flagship car.

2008 STI: whole new chassis, new DCCD(revised AWD), new suspension structure(inverted suspension in front)

2011 STI: revised suspension(50% stiffer spring than 2008, according to CAR&DRIVE), bushing and suspension related parts redesigned, new sway bar.

2015 STI:independent and whole new chassis, hugely revised suspension(much firmer compared to 2011) but it's as comfortable as GR, revised steering ratio etc.

2018 STI: whole new DCCD again!(fully electronic), 6 piston brake with brake duct

Is 2018 STI much better than 2008? Yes. Handling is better and better.
Compared to other competitors in same class, STI doesn't share the same chassis with daily driven cars anymore. It's a huge step for STI.
Chassis balance is always the first priority when it comes to sports car.

The most exciting part is: will the new TypeR be faster than 2018 STI, which are both revised year by year in past 15 years? Subaru intentionally changes OEM tire for MY18 from crappy Sport maxx RT to Yokohama(same grip as PSS). I think they do this for better test result.

Now they two both have 305hp(US spec TypeR 306hp) and similar price.