I have a 90 245 and recently my speedometer cluster burnt up and bit the dust. A local shop procured a replacement, however they sourced a K10042 instead of the stock K9800. From what I'm reading, the K10042 was the sedan speedo geared for smaller tires, while the K9800 was for wagons with their larger tires. Also I read something that said it might not be just a straight wagon/sedan difference, but one for ratios in the drivetrain from manual vs auto trannies. Dropping this in, what issues might I see? I'm not running stock tires anymore, my summer sets are iPd Pegs with 215/45R17s.
Basically if I were to use this speedo, how off would I be? I read something like 2.5%-5%, so I'm guessing I'd be going faster than indicated?