well its standard power, lowered and a welded diff so drifts awesomely! the front bumper is pretty beat up yes but if your looking at drifting it theres no point of fixing it properly as your only gonna break it again. i normaly just have it held on by a few cable ties so if it comes off it comes off easily
as for the subframe, its not the frame you need its just the bushes im sure you can get them from the dworks shop, or you can just use locking collars which im sure you could find on here.
i dont know what group insurance an s13 is. sure someone does