I have done lots of searching and could only find one post on the Webb that gave a description of the differences in the B&S Intek V-Twin and Professional Series V-Twin series motors. The post was from this forum in 2012 that stated it was nothing but the Air filtration systems. I would like to ask for a confirmation or if there is an updated, or more accurate information between the two if possible. There is a $60.00 and 7 AMP alternator difference is all I know. One will be replacing a CC ZTR Mower discontinued 18HP Intek. Briggs & Stratton 445577-6187 23 HP Intek OHV. Briggs & Stratton 44L777-0132 23 H.P. Professional Series. All the hardware specs are the same. Is it just the air filtration? Thanks!