for that to be a fair weight savings comparison, you will need to remove the shields and use stingers.
i looked into the pi pipes long ago and they work, kinda. like most pipes they only really work if you can keep them hot. to really keep a pipe hot, you need to wrap them or stop all the air from blowing over them. coating helps but is in no way as good as wraping pipes. i had talked to a guy that had dynoed the pipes against the stockers on the same day and when they are cold or mildly warm they make couple less hp, when they are hot, really hot, they made 8hp over the stock pipes. like he reminded me, it is really easy to get a pipe really hot on a dyno, there is no 100mph of cold air blowing over them through all the vents. with srx pipes, the temp they are hot on the dyno is very similar to the real world temp. so after my conversation, he said, yes they are a great pipe, have them coated so they wont rust, then wrap them so the air wont cool them off.
if your just in it to make the sled look cool, remove the stock covers, install a can and crome the stockers. the pipes look better than the pi pipes with the covers off. the srx pipes are stamped, not hydroformed.