Comptech sport springs are very similar to the itr springs. I used to have them on my previous gsr and they were decent on the streets, great on freeways. You can find a used set for about $100. All aftermarket springs will fit your agx's as the spring seats are the same diameter. I wouldn't stay with stock gsr shocks unless I needed a temporary solution. They will go bad quick with stiffer and shorter springs. I recommend you also get some koni bumpstops as they help lessen the impact of bottoming out and keep it from upsetting the suspension. Eibach prokit rates are close to the itr's too. Just stay away from the sportline because it's progressive all around and your car will undulate from side to side.