If e-Frontier follows previous upgrades (and I've gotten all of my Poser versions through them) then P7 will install to it's own directory and leave previous versions sitting just like before.  It's actually pretty neat the way they do that.

As for Runtimes, Pakled, my props runtime alone is 35 Gigs - I'm such a props junkie! 

Hugz from Phoenix, USA

Victoria

Remember, sometimes the dragon wins. Correction: MOST times.