of course it will make you a better driver,, if the porsche have more horse power, better handling, then who will win the race? the much better equipment of course ,the porsche,,It sounds as if you are asking whether or not the D90 will make you a better photographer.
Answer this question...
If you trade a BMW for a Porsche, will you be a better driver?
Hope this helps.
so if you can afford a d90, then go for it,,