ebay has the best prices on bilstien shocks and struts. just search for "bilstein mustang" $480 for shocks and stuts shipped. now that being said if you buy the starter box from maximum motor sports it is a good deal as as a package. I got some parts as gifts but I have all the parts that are in the starter box and the cost was roughly the same just in my case cc plates and spings came as presents.
the bullitt suspention is not bilstien it is tokico.
the bilstein setup is not going to be optimum for strip. to stiff. handles great but for optimum weight transfer you would need softer suspention. the is not "great" combo suspention. my car is driven way more on the street than the track.
tokico ILL $450
koni reds $550
if you have deep pockets look at QA1. they make nice ajustables that are rebuildable as well they are just the must expensive. they are right up there with koni DA in price.
I almost got the koni but with my stereo it is a pain to get my side panels out to adjust the rear shocks so I just went with a fixed shock.
my .02 if you want combo would be to set up for handling and then buy a pair of slicks for the track. If you setup a drag suspention you will suffer though the corners.