Sounds great. I might do the same. For you I would simply advise driving with your current kit a little bit more, getting used to its power and delivery before moving up to the 550 and then 575. You just got your kit installed and barely acquainted with it. Besides the weather is still not warm. Drive it a bit in warm weather, then hot- enjoy it and spend more time with it, then go for it. There really isn't any hurry to upgrade that much- let ESS work out some of the testing and expecting kinks in the first production run. These kits are a blast and will last for awhile.
2003 M3 DIAMOND-METALLIC INDIVIDUAL
ESS VT2-500+ SUPERCHARGER/MODIFIED B&B EXHAUST/RD SPORT CROSS-FLOW MID-PIPE/GROUND CONTROL COILOVERS/CUSTOM 19" 3PC FORGED WHEELS