It'll still start if you do that, but it'll throw a neutral safety code, I seem to recall.
First off...there is NOT a neutral safety ANYTHING in a manual trans subaru. There is a clutch switch interlock, so you can't start without depressing the clutch. No codes for ECU not connected to ECU.
Nuetral switch in trans is to tell ECU wether it needs to idle rolling in nuetral to a stop or let you keep rolling, pushing the engine when in gear.
It may not start actually. It must see the cranking signal to properly set mixture for cold starting. Many people end up with no starts on EJ swaps from not connecting the start circuit to the ECU. Sometimes it will still start, but with excessive cranking needed.
Alright, I think I've talked myself into replacing just the solenoid contacts, instead of the entire starter. I can pick those up - with a plunger - for under $10 on eBay. It's not that complicated, I guess. And I have to pull the starter either way.
Now my big concern is, can I replace the starter from the top? I don't have ramps or jack stands and I try to avoid climbing under cars that are only held up by jacks. Getting it out doesn't look too difficult (famous last words). It looks like there's enough room to lower the starter down after removing the 2 bolts. Then I could simply reach under there and grab it. But putting it back in could be a problem, though...
Ebay plunger sets are notorious for being incorrect.
contacts may work, but the plunger length may be wrong. I stopped buying any Ebay parts they've gotten so bad. Just be careful.