pr (by region) with a top-up bonus for the top vote getting party or alliance of parties.
The relevant part though is the thresholds - 4% for parties running individually, 10% for alliances, 2% for alliances' individual member parties. This is low enough to ensure representation to the Lega Nord and CCD-CDU (Berlusconi's smaller parties) but may be fatal for the smaller partners in the Ulivo.
This choice is in order to maximize advantage for Berlusconi:
center left have a people who votes for coalition, but dislikes single parties of it.
In the ballot you have for each party the party symbol, you can't choose the candidate. Every party has a locked list. So, knowing polls and trends, the selection of elected people is made by party leader.
All this leads to a campaign at national level, on TV fields. And Mr. Berlusconi is the owner of the three most important private channels, and choosed managers of two most important public channels.
In the Senate the bonus if for each region, so you can have a different majority respect House.
In the House the bonus is very small, you have a 50 deputies majority (340-290). So, who wins depends by the will of 25 people.
Berlusconi, forecasting the bad result, prepared a low majority and turmoil system.
