In 1999 Saturn SL2 engine (DOHC I4 LL0) compatibility?

I just bought a Saturn SL2 mileage as a commuter car. I liked the fact that most use the old Saturn I4 engine (both SOHC and DOHC versions), so it would be an easy solution if the engine is out. I read somewhere that the Twin Cam 99 can be exchanged with another engine Twin Cam 99, is this true? "A review of the LL0 published in 1999 and used a camshaft with roller hydraulic lifters and rocker "It's the only difference between the twin cam 91-98 most older engines and new engines of 99-02, and it is in the head. Why limit what I can swap in my new car? I mean as long the engine mounts line up I should be able to use any Saturn I4 engine that I want, SOHC or DOHC. Or is there another reason I do not found? I think the guy who posted this trying to exchange and OBD1 motor into OBD2 car and that is why he said it would not work not.

1999 SL2 has an electric smog pump if u can use a cul 1991-2002 bottom but u must use the head 99 due to the smog pump and motors 2000-2002 are different because they have an intake manifold is plastic so u have to design and adapter is a pain in the ass. But as I told u may use a cul substantive 1991-2002

1997 Honda Accord Fixer at Now Ventures Rancho Cordova #3388