Driving with H & R lowering springs...
Soft but need more suspension travel....
Does adjustable lowering springs offer more travel ??
Or is K-sport Coilover kit the best street solution.??
I'm assuming by adjustable springs you mean coil over sleeves? Can't say for sure what to do, but if it was me I'd stay away from those if you're concerned with handling, which from the sounds of it you are. That said, if you're interested because your springs are too low for you and you want to be able to be a little higher, might not be a bad idea.
The simple truth is that these cars can't take much lowering, so you might have to recalibrate your idea of how low you can go without running out of suspension travel. You don't necessarily need coilovers; Your first option could be to find some properly valved dampeners to match your springs, that might be cheaper than coilovers; I think the KYB AGX's i've read about having the shortest shock body out there for us and so work well with shorter springs.
Coil-overs are always going to be the best bet if you go with a good brand because the springs and dampeners are made to match each other, so you're going to get something that a.) works most effectively in a small travel range and b.) has been tailored to work with the existing suspension geometry as best as possible. Yes it's possibly to figure these things our yourself and come up with a setup that will be as good, but short of just copying someones car that you know handles the way you like, after all the time installing/reinstalling things to get them right, a coil-over setup can save headaches.
But, i'm biased. Also, i've been looking at the k-sports myself.