Usually you do not need a control box when you install a can and y-pipe. In rare cases, you don't need one for a pipe either(My buddy installed a BMP stealth-pipe and Y-pipe on his F7 without using a box). I've heard of people having to use a control box when they've just installed a can only so I guess it varies. I'd go with a boondocker control box, i've never used one but have only heard good things about 'em. They go for 419.00 the last time I checked. You can find them on www.bikemanperformance.com and also at several other places.
Here's a quicker link..
http://www.bikemanperformance.com/products/product_info.php?cPath=41_24_195&products_id=154&osCsid=7e58335126c83a7b49ac41ce76255280