If you want a S2 engine you will have to buy it used (Buick stopped making/selling Stage motors in the mid 90's if my memory serves me correct) or you could build a serious Buick V6 engine using the new TA Performance aluminum block and TA is also making new aluminum heads......... Here are some links to info about the new TA block............
http://www.taperformance.com/v6_block_flyer.htm
http://www.taperformance.com/initial_press_release.htm