The full cooler kit won't necessarily get you much more power but it will keep the power consistant. You might might make 300 on the dyno with those mods but once the standard cooler heats up, so do your intake temps and your power will suffer. There is a thread on what mods to do to your FG in what stages if you do a search. Well since you put it that way. Don't touch your car lol. Just get your tuner to do it. Both tuners are pretty much spot on. The only way to test if your valve springs will be ok is to run it up on the dyno, but until then you want know. The prices are about right for supply and fit. If you sourced the parts yourself and could do some of the work you would save roughly $500 or more but that's not an option in your case.