Pasta must always be cooked as close to boiling over as possible.
it 's essential that you drain it out while still quite chewy. Once you mix it with a sauce it will absorb the sauce and soon become cloggy and soft, so it must be eaten immediately. Keeping it warm for more than ten minutes isn't a good idea.
Italian restaurants often prepare pasta in advance, but you must take it out of the boiling saucepan while it stil has a slightly hard inner texture. Pour it into a coulender and run cold water over it......this stops the cooking process.
Within 24 hours put in a large frying pan together with the sauce and a small drop of water and heat stirring frequently, and most important taste for the right chewy consitency which arrives fairly quickly. Beware, If you exceed the heatig time you'll end up with a gluey mess, but if done properly it's almost indistinguable from pasta made the same day. Some trial and error may be necessary.
Good eating.
chick 56 from Italy