JB, if you like the ride with the factory springs, you could keep those and install 2-inch lowering spindles. The only thing worse than too weak springs is too strong springs. OK, maybe messed up camber fits in there somewhere. Until you get it set up the way you want, I wouldn't replace that bumper cover (buy it, paint it but don't put it on). Not that I would know anything about that kind of stuff.
The springs I have are a little stiff, but not too bad. I've considered lowering spindles but eventually I want to get bigger brakes off of a C6 Corvette and with lowering spindles they could cause interference with the wheel.
I don't plan to replace it until I get all of the mechanical bits figured out, just lots of mechanical bits to figure out first. Good news on the tuning front the idle is working great now, I'm about to call it done once I can do some good WOT (wide open throttle) pulls and test the AFR (air fuel ratio) with power enrichment activated (like the power valve on a Holley carb.) But to do that I have a slight exhaust leak to fix first, one of my V-band flanges warped when I welded it and I'm just going to replace it and have it done "right" this time.
JB


Here is a look at the bumper cover before I reattached it:






