  We report on the results from our deep Chandra observation (120 ks) of the
supernova remnant (SNR) N49 and soft Gamma-ray repeater (SGR) 0526-66 in the
Large Magellanic Cloud. We firmly establish the detection of an ejecta "bullet"
beyond the southwestern boundary of N49. The X-ray spectrum of the bullet is
distinguished from that of the main SNR shell, showing significantly enhanced
Si and S abundances. We also detect an ejecta feature in the eastern shell,
which shows metal overabundances similar to those of the bullet. If N49 was
produced by a core-collapse explosion of a massive star, the detected Si-rich
ejecta may represent explosive O-burning or incomplete Si-burning products from
deep interior of the supernova. On the other hand, the observed Si/S abundance
ratio in the ejecta may favor Type Ia origin for N49. We refine the Sedov age
of N49, tau_Sed ~ 4800 yr, with the explosion energy E_0 ~ 1.8 x 10^51 erg. Our
blackbody (BB) + power law (PL) model for the quiescent X-ray emission from SGR
0526-66 indicates that the PL photon index (Gamma ~ 2.5) is identical to that
of PSR 1E1048.1-5937, the well-known candidate transition object between
anomalous X-ray pulsars and SGRs. Alternatively, the two-component BB model
implies X-ray emission from a small (R ~ 1 km) hot spot(s) (kT ~ 1 keV) in
addition to emission from the neutron star's cooler surface (R ~ 10 km, kT ~
0.4 keV). There is a considerable discrepancy in the estimated column toward
0526-66 between BB+PL and BB+BB model fits. Discriminating these spectral
models would be crucial to test the long-debated physical association between
N49 and 0526-66.
