Start With "IN" Connect Prior - Performance is Awful

Howdy,

I'm new here - so assist me if I've posted in the wrong area... please.

The following two queries should provide exactly the same results.

SELECT  CONNECT_BY_ROOT(IXKITL), LEVEL, IXKITL, IXKIT, IXMMCU, IXCPNB/100 SEQ, IXITM, IXLITM, IXQNTY/1000 AS QNTY
FROM TESTDTA.F3002
WHERE IXTBM='M' AND IXMMCU='     2620001'
START WITH IXKIT IN (SELECT DISTINCT SDITM FROM (SELECT SDITM FROM TESTDTA.F4211, TESTDTA.F3002 
WHERE SDITM=IXKIT AND SDMCU=IXMMCU AND SDMCU='     2620001' AND SDNXTR<'560' AND SDPDDJ<115108 AND SDITM != 0 ) )
CONNECT BY NOCYCLE PRIOR IXITM=IXKIT AND  PRIOR IXCMCU=IXMMCU;

SELECT  CONNECT_BY_ROOT(IXKITL) SO_ITEM, LEVEL, IXKITL, IXKIT, IXMMCU, IXCPNB/100 SEQ, IXITM, IXLITM, IXQNTY/1000 AS QNTY