I'm not sure about the brand but they may be described as black 5-spoke wheels with polished lip. This exact style is not currently popular but you can buy full black versions and a few other colors.
See pages 3, 4, 5, 6, and 9 to see examples.
Wheels for 1998 Lexus SC300 (tirerack.com)
Some shown are larger in diameter than your OEM wheels which I believe are 16-inch diameter. Here are the specs for one of the aftermarket wheels of that size:
Focal F55 Black Painted (tirerack.com)
Size:
16x7
Offset:
+40mm
Backspacing:
5.590"
Bolt Pattern:
5-114
Rec. Tire Size:
225/55-16
Weight:
18.7 lbs.
Finish:
Black Painted