There was still a bit of weight to the suit as well. Foam rubber is light in theory, yes. But when it's run as dense as those suits where (I've held pieces) and in that size the weight picks up. The cape was over 50lbs. that added to the bodysuit.
I'm aware of an '89 suit at the Peterson Auto Museum, a few in the Warner's archives (1 being the on that was on display in the museum), I BELIEVE Prop Store has a partial in the London office as well as a Nicholson costume, there's the production pieces Shawn's "partner" has (full body armor), some production pieces that PJ has (just legs, forearms, and calves), and one full screen used suit in the hands of a private collector. There's also a full '89 at Elstree Studios in the UK.
And then Returns, Theres a few in the WB archives. Propstore LA has one (bodysuit, cape, and cowl), PJ has a production made cowl, and I know of three private collectors, one with a bodysuit and armor, one with the "driving" suit armored from the waist up, and the same collector with the SU '89 has a SU Returns. There was another auction site to sell off a full Returns as well. I think it may be a relatively recent PiH