It's not going to be a super hero costume.
"Logically" (from the look of it) it'll be a pressure suit to cope with the relative multiples of air pressure he will be experiencing, once he's reduced to ant size even if he is approximately the same equivalent mass/weight depending on how they explain the fake science of Pym Particles... And lets face it, air will be too massive for him to metabolize like how O'Brien and Bashir had trouble that time in One Little Ship, so he'll need a scuba rig minimum.
Man in an Anthill, had Pym getting lot in a tiny alien environment.
Marvel Premier, had Scott nicking an old Antman costume to rescue his daughter from a bastard.
Irredeemable Antman had shield agent /security guard Eric O'Grady "borrow" a next gen Antman suit while the Hellicarrier was under attack form bastards to save his ass. Not save the day. Save his ass.
If you mix that together what do you get?
Die Hard on the Hellicarrier.