We implement a non-trivial and renormalizable extension of the NJL model. W
e discuss the advantages and shortcomings of this extended model compared t
o a usual effective Pauli-Villars regularized version. We show that both ve
rsions become equivalent in the case of a large cut-off. Various relevant m
esonic observables are calculated and compared. (C) 1999 Published by Elsev
ier Science B.V. All rights reserved.