I've been looking around for options to replace the rear shock and have only been able to find two. the racetech rear looks amazing but is quite pricey at around $1300 and the only other i have been able to find is the Elka shock that is the spec for the Canadian CBR250R Challenge race series. The Elka is a little more wallet friendly at around $600 but looks to only have rebound and preload adjustments. doesn't the stock rear shock have the same adjustments and if so what would make the Elka any better?