I am fairly certain 45mm was standard for the 996 (bip model) my 998 Bip had stock 45mm cans on when I bought mine new. If you can get hold of an Ultimap chip then go for that, but they have long been out of production. The one they did for the 748R was proven to make a big difference to the running and cured known problems with the bike. You could try JHP as they used to sell chips and I wouldn't be surprised if they still had a few suitable chips for sale. They used to market "their" own cans at one time so they must have had suitable chips to offer. Having got a set on my 748R engined 748S I reckon they were Termignoni's that had been rebadged though.
I'm going to assume (normally fool hardy) as its a MY2001 it will be double unless someone unplugged the 2nd ones.
I would check just to make sure, if it was me. I suspect it should be double injector but there is no point in throwing money away. Again, if it was me, I would ask what I can expect for my money and how it would be expected to work, given my setup. I have always found JHP to be good on information and customer service, but how would they deal with a chip that is not working on my particular bike? It's worth asking the question upfront so that both of you know what to expect. They do have a lot of experience so, in my opinion, a few searching question are justified.
