stiffing up s-chassis??

[turbo2nr]

i have a 97 s14, 120k on it. the car chassis wise feels loose as s*it. the car just doesnt feel solid anymore, going over bumps and uneven roads everything feels loose and sloopy. i live in nyc and the roads suck that and add coilovers i guess it finally took a tole on my frame.

so what can i do to possibly stiffen back up the car? i was going to start with checking over all the bolts that attach the front/rear subframe to the car. i have nismo mounts and spl collors. i was going to get spl diff bushings because when i let off the cluth the rear chatters, also if i shift hard form first to second ill get wheel hop then the tires just spin.

i was also thinking of a power brace for the front and possibly fender braces i heard that it does wonders..

any suggestions will help. i do not want to cage the car. so that is not an option.

thanks