I have a dozen Powerage products, and I recall a problem with "Residential".  My note from some time back says Blocks 4 & 13 crash Carrara Pro 8.5, with or without vegetation.  I recall the rest of the product worked to some degree - there are 14 total blocks.  I apparently tried something that also did not work, but I don't recall what the notes mean: "H4 Zero - Crash", "H13 Zero - Crash" (note the same numbers as the blocks).   I'm heavy into another animation so will not get back to this for a while, but I hope the "Powertown" workaround may help with "Residential".