I have the set-up described above. First, not only the R cars came with sport suspension(std), some 850T & T5(like mine) came with it as an option. Also, the major diff. bet the sport & non sport suspension was thicker AR bars & stiffer springs. Note also that all 850s ride harsh(compared to a toyota or honda), but thats due to the chasis set-up. Anyways, I have OEM sport spring with bils in rear and Konis in front set to soft. I recommend this set up! Your squat & dive is eliminated and the car handles fairly better(less bouncy feel). Like I stated, if you have OEM sport springs, you'll still feel the bumps & vibration. If you want to have smooth ride stay with 16" wheels and 55 series tires. I have 17" & 45 so you know i'm get more "sensation" on bad roads. Also, get the best tire you can afford, since it will make a big difference in noise, stopping, grip, etc. If you have regular OEM springs, you will be fine in comfort. try shox.com for best prices!!