Thats a lot of work. Guide rods are a royal pita, and depending on which shifter bushings you are talking about the shifter needs to come out and apart to get to most of them.

$650 sounds good, besides you are bringing your own parts the shop needs to make money somewhere.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200