I am working on a 2000 SSEi with 123K. After doing some research here I have decided to replace the LIM Gasket, VC gaskets (leaking), Thermostat and flush the coolant. I have bought all recommnded parts. I found the best prices at Oreilly'*.

Fel Pro Gaskets:
MS 95977-1@ $39.99
MS 95744 @ $9.99
6102 (TB Gasket) @ 4.49
VS 50465R (V/C gaskets w/ grommets) @ $49.99
35595

Dorman 47065 Heater Hoses @ $3.69

195 Thermo and Gasket

BWD Injector seal kits @ 3.29 x 6

Question: I need to drain the system to replace the LIM gasket and related parts, should I replace everything then flush the system or is there a way to flush it while I have everything apart?

What I do is remove the thermostat and then use a shop vac to suck out some coolant. You just need to get the coolant down to the level of the heads. After you remove the LIM some coolant will drip in to the cam valley. Have a clean rag handy to dab up and coolant. Be sure to get it all. Then pour a small amount of oil around the cam and bearings to wash out any coolant that might be there.

I suggest getting a new set of coolant elbows, I think they cost about $5 or so.

Yeah - the Dorman part number above is the "coolant elbows."

Managed to get most of the wires out of the way. The Alt removed. TB and rails off. I snapped a few pics. If you see something that may need attention, please feel free to add your 2 cents...

Clean the throttle body real good. And use a little spray lube on the injector O rings.

I bought an injector seal kit that has 2 new O rings in it for the injectors. Should I replace them all?

U coulda got all 6 from ZZP or even rockauto. Id say it wouldnt hurt. atleast u wont have to worry about any of them failing anytime soon.

Lubing up the O rings will make your life easy, I forgot to and ended up destroying a set of fuel rails

Nothing wrong with replacing them. Keep the old ones as spares.

Here'* how it looked before cleaned and then cleaned up ready for reassembly.