I totally understand your thoughts... i can say that i have a few friends that went down the same route, some opting to go smaller an d stay in a 3 series (as their only vehicle), they all now wish they had the handling and versatility of the GT, and two friends that opted to not get DHP, i can tell you the two of them regret it...not that they dont love their GT as is, in both cases the cars are leased and the small monthly increase detered them, until they compared their cars to ones with DHP.
My next door neighbor joined the club last month taking delivery of his GT 335ix with DHP and he loves it... the 335 engine kicks ass is plenty of power for just about any normal or abnormal driving situation... But it is the DHP that holds this car steady and level around turns or through evasive driving maneuvers.... there will never be a time that you ill say eh i didnt need to get the DHP, but there will certainly be times when you wish you did......often it will be as you recover from crazy turn to fast or a quick lane change because of the idiot that just cut you off, and right after you get your heart out of your groin, and you thank heavens you didnt **** in your pants you will sit back and say ....Damn that Mpress guy from bimmerfest just saved me a trip to the dry cleaners.....
what ever you do you will love the gt......
2012 GT 550ix Msport (feb12)(ok early march 12)
09 X5 4.8
12 X3 35i (the wife)
61 356 roadster