nah they are reloop rp3000s from memory
the mixer i paid 350 brand new and its hardly used
the decks i paid 400 for agessss ago
happy to get let it go for 225
theres another equalizer you can have too
its an old shit one, but works (no fancy display)
you might have a basic water pump issue or some sort of flow issue
90 isnt that bad, but it shouldnt move past 90
ask the engine builder?
the n1 water pump flows less at idle vs stock as its designed for high end RPM high flow
so at idle, it will actually be outperformed by the std water pump in terms of flow
when did this start? since the radiator change?
check the basics etc
dont goto a workshop for something basic like that
read what the others have posted
learn how to debug and fix it yourself
the ECU has on board diagnostics so theres nothing magical a workshop can do that you cant find out
no it wont be the alternator
check the airflow meter plug, make sure it is secure
look for any damage or excessive dirt etc
reset the stock ecu (undo battery terminal in boot (the ground cable) and press brake pedal)
if it still happens you need to get a consult cable and run stock ecu diag