Just bought this 1989 Nishiki 12 speed. (not my photo, this one I found on-line, but identical bike). All original components, Shimano Exage, right up to the handle bar mounted shifters. Mine has a different seat, and some Look pedals. I am just getting started back into riding again and running on a limited budget. Are these shifters Ok, or would you switch them out? (Maybe some STI’s) I need this bike to carry me for a bit until I can buy a nicer one to get serious on.