The Koni Yellows are adjustable only in ride stiffness, not height.
If you absolutely must have these H&R springs, then by all means....but you will still have a 2.5" drop if that's what the springs are. You will then need a camber kit to correct any camber/toe issues. This equals more money.
The Koni Sport (yellows) are a fantastic shock. My advice to you would be to match them with a great spring. Now there are a few ways you can go about this decision..... Two basic setups if you will:
1. Koni Sport shocks+Lowering springs (Eibach, H&R ect.)+Anti-roll bar.
2. Koni Sport shocks+Ground control Coilovers+Anti-roll bar.
The first setup will be awesome. Ride stiffness adjustibility+a spring rate matched to your specific car (buy a spring that drops your car no more than 1.9"). The Anti roll bar is key, but if you cant afford one now, then it can wait. Keep in mind a good anti roll bar is probably the best upgrade you can do to your suspention.
The second setup will kick ass. You have ride stiffness and height adjustability and you can custom order a specific spring rate if you want from ground control to futher customise your setup (the commercially available GC's have a spring rate around 280lbs). Ground Control coilovers use Eibach springs similar to those of the sportline series, so ride quality is great. Then, as always, a good anti-roll bar will totally take your GSR to a diffrent level of handling. This would be the setup I would most reccomend.
In terms of other shocks, kyb's are a good street shock, but will not be taken seriously in Auto-X. If you can't afford the Koni Yellows, then you could possibly downgrade to the Toiko Illuminas...but once again, they are a great street shock, but nowhere close to the Koni's.
Cheers.