Doing my homework on Suspension

I have thought about getting lowering springs, but way too many people have slapped me and told me, do it right the first time so you never regret and never waste money. Now im doing my homework on coilovers, cuz for the following weeks i will be buying.

There also came to an arguement of 2 of my friends that changing the suspension setup (specially for celica gt-s) could cost me worse handling than it already has. Since celica's suspensions were made to take corners like a Gran Tourer. Their already perfect/stiff handling could make more improvements by increasing rigidty of the chassis (i.e brace,bars,rolls).

Im not really into lowballing. Meaning expenses is no problem in choosing my suspension. I do want is performance and reliability. I have considered straight JDM (trial, zeal ~so on) but there's great cost, and unknown performance/reliability (for people with these suspensions, please enlighten) Zeal, i know is really good/expensive (i've driven my friend's WRX with zeals and bodyroll is like somethings from the past)
Tein SS-P /w EDFC i can probably rely on, since they can do overhaul if anything goes wrong, but how is the performance? I know for fact that there's always another that outperforms tein. JIC is infact a great coils... for tracks that is, and im almost certain im daily drivin my car, so i was suggested that it might be to aggressive for me. Others have been suggested like hotchkis, and TRD ~ but they said TRD is way too expesive for its performance, and hotchkis isn't as good.

I know that suspension choice is solemly mine, but i want the people with these suspensions to shed some light and share their opinions on performance/reliability/satisfaction since no one knows more than they do. And believe me, every of your opinions count. Thnx