As you've probably gathered, every baby is different. I just wanted to say that although its worrying thinking of your babies coming early, you're past 32 weeks which is absolutely fantastic and the fact that the hospital thinks your babies are going to be early means they're on standby, on notice, and they're doing everything they can to prepare you and the babies for birth. As some of the others have said, by 32 weeks, their lungs are pretty much formed and although they might need a little bit of help and watching if they were born now, they'd generally be just in hospital to make sure they could regulate their own temperatures (prem babies aren't too good at this) and to get used to feeding. The only complication really is it being twins - not from a medical point of view so much but an emotional one. You will automatically compare them - if one is bigger than the other, or if one is slightly better at breathing than the other, and worry about the one which isn't doing as well. Its a stressful time but you WILL get through it :-)
I had twins at 27+6 - both were 2lb 6oz. They were in hospital for exactly 2 months - Twin 1 didn't have any help with her breathing at all until Day 9 when she needed a little bit of CPAP for 24 hours, Twin 2 was ventilated for about 12 hours and then he had CPAP for a week or so. They were tube feed to start with but we established breastfeeding before they came home. It was a bit scary going home with them after so long with medical staff on hand but we had lots of support from the Neonatal Unit's midwife who visited us at home every other day or so at first and then every week.
They had regular check ups with the consultant until they were 2, at which point he signed them off as having properly caught up. I don't think they were behind their peers too much - smiled, walked, clapped etc all around the same time, but their speech was probably about 3 months behind (am convinced this was a twin thing rather than a premature thing - they just seemed to communicate with each other without saying proper words).
They're 6 now and you'd never know - we were told at parents evening that she has a reading age of 11+, has a real flair for vocabulary etc. Twin 2 is a typical boy, probably just as bright but more interested in playing football and rugby for his local teams.
Sorry I've gone on, but I was desperate to hear positive stories when I'd had my babies so early and call me baised but I think mine is fairly positive!! Wishing you lots and lots of luck with your pregnancy.