PPC G4 7448 in a PowerBook

One could think that the PPC G4 had reached its end of life as a notebook processor; but it is not the case.
A company, Daystar, is proposing to install the last version of the PPC G4 aka 7448 featuring 1MB of L2 cache and clocked at 1.83GHz in PowerBooks.
BUT.... only the PBG4 1.67GHz can be updated with this processor, the previous model do not support it. So even if the larger memory cache as well as the speed bump will ensure a real increase of performance, this offer will be limited to a small number of users.