what do ppl use when they do twi cam head coversions to 2.6l???

There is no twin head cam head for the 2.6L.

what do ppl use when they do twi cam head coversions to 2.6l???

2.6 is a slow revving, low down torque engine. No advantage in twin cams, unless you get a workshop to make one, and have cams ground for more revs. And then you would blow pistons or bottom end.
So, in short, no point and not available. Hence not possible.

Check out Toyota engines if you really need a twin cam engine.

Check out Toyota engines if you really need a twin cam engine.

Or try out a 4G63 out of an older model GSR...