well if you get d4 ohm subs you wont have to run you amp at .5, you wont need the cap that does nothing anyways, and then you can do big 3 later on if you happen to have any dimming issues.
sell the type r's on ebay, and you'll get jsut about what they go for on there, then turn the money around and buy some d4 ones from ebay and you're set.
i don't think you're gonna notice any SQ difference between 1 and .5 ohms
but regardless, why are you thinking about all this AFTER you bought all the equipment?