any kit thats worth while wether it be an inexpensive one or a high end one will only be relatively inexpensive if you aren't looking for HP. running about 500-550 HP will cost you no matter how you do it.

the edelbrock kits are okay if you can stay within their programmed parameters. But since you like changing things so much i would recommend either the megasquirt or accel DFI or FAST EFI. those kits allow future expandability that you really won't see with the edelbrock.

i'm in for about $1500 total on my megasquirt setup. the key is not rushing and finding the parts used or on ebay. once it comes to EFI all makes of parts are fair game so theres plenty of aftermarket available.