Welcome Mark! Re rattle, def get that fixed asap, especially as they worked on the car before you took ownership. Re throttle hang, its across the ZRE range, almost all years experience it. Most of us that have modded our ZRE's have found that with the intake changed (to SRI or CAI) the hang is reduced, and even further still with headers or full cat back system swaps. I know its a bit of work, but it annoyed the hell out of me too, and many others. Re springs, I was more than impressed with the Eibach springs i purchased, very high quality for the price, ride was terrific.... Im not a fan of Kings, but others have had success, most have swapped them out for other brands. Lovell also do a nice set, and with the most drop for off the shelf springs. Depends how low you wanna go :) Hope that helps