FMIC purchased SWR to increase their offerings to the bass community and to offer dealers more choices when stocking their stores. There was no interest in changing anything about the "SWR sound". The SWR and Fender brands had very different tones, aesthetics and "vibe", and co-existed well on retail floors.
Great pains were taken when production moved into the Fender facilities. Several key employees remained with SWR and were integrated into the FMIC manufacturing facilities, teaching others how to build SWR along the way. The original SWR designs and circuits were carefully reconstructed and documented to keep the sound and performance intact.
Although SWR and FBA® (Fender Bass Amplification) necessarily shared some resources, they had separate Marketing, Artist Relations and, of course, Electronics R&D teams. There was a good deal of friendly competition within the offices.