Dell Venue 11 Pro - Dell Netready (HSPA+) with O2 sim card

Hello everyone

I would like to buy a Dell Venue 11 Pro but it's essential for me the presence of a cellular modem (3G/HSPA+) to get connected wherever I want, without a wireless point.

The Italian Dell website offers two solutions: one "for companies" with a Dell Wireless 5570E (3G/HSPA+) cellular modem, and one "for home" with a Dell Netready (HSPA+) with O2 sim card cellular modem (CNV1M02 model). Since I am a private without VAT, I don't think I could buy the solution for companies (am I wrong?), so I am forced to buy the one with O2 sim card.

What I would like to ask is:

1)Which is the difference between the two cellular modem? Do they have different performance?

2)If I buy the one with O2 sim card, will I be able to use the cellular modem with another sim card (O2 is quite exspensive) or is the sim card blocked in some way (hardware or software)?

Thank you so much

Best regards