how much plexus are we talking?
No I agree a new GAHH soft top will greatly improve the appearance of the car but new wheels and an aero kit is more than an improvement, more like a re-invention.
DPS autoparts sells the bumpers and sideskirts for the 986. I'm sure Dayton over there has looked into sourcing for the 987. They sell on ebay as DE parts.
p.s.
There aren't really GT3 sideskirts for the Boxster. Porsche only makes one style factory in polyurethane for the Box, Like the one in the link I posted. Other styles (like the GT3 on my car) for the Box are made of fibeglass which is cheaper but more fragile and only produced in the aftermarket and usually cheaper than the factory polyurethane.
996 GT3 with errr GT3 sideskirts