I am in the process of rebuilding my engine. I am using semi-stock 2.0l heads. I am using stock valves however two of the valves were damaged (1 intake, 1 exhaust). The remaining valves are in excellent condition.

-Would it be best to replace the broken valves with a used intake and exhaust valve or replace all of the valves with an aftermarket type?

-What aftermarket stock sized valves are out there? Are they an upgrade or downgrade?

-Do I need to have the seats re-cut when I replace the valves (the heads were recently reworked with new seats, guides,etc)?

Don't know about the aftermarket valves, you can use clover lapping compound on the two replacements. That's only if they were done very recent. You can usually see pretty quick during lapping if they are going to work. IMO even brand new valves should be touched up or at least checked.

The one thing that should always be replaced at rebuild time is valves. I'd rather reuse engine bearings as valves!

Where can you buy stainless valves?

I searched t4store, PP and AA and I couldn't find any.

http://www.europeanmotorworks.com/

We stopped selling them last year.. It seems that no one knew what sizes they actually needed and orders were always confused..

http://www.sivalves.com/