You'll find no noticeable difference for street riding in the low end Ohlins forks & shock as far as comfort goes. Actually, IMO the suspension you have is as good or better than the low end Ohlins stuff.
Actually the Stock Suspension on your K8 is not to shabby. With a little fine tuning it will perform very well. Of course the springs are the big issue if you are a heavyweight. And the rebound damping on both forks and shock leaves a little to be desired but it works quite well.
Personally, I wouldn't waste my money on Ohlins Suspension unless I had the ability to over ride the stock suspension.