In short the answer is Digital Horsepower
Search at regalgs.net or clubgp.com
Both sites have a wealth of information on uprating the gm 3.8l engine.
The engines can easily be upgraded mild power with more serious amounts with hardware upgrades.
The 2011 Buick Regal's engine produces 182 hp @ 6700 rpm.
The 2001 Buick Regal's engine produces 200 hp @ 5200 rpm.
The 2002 Buick Regal's engine produces 200 hp @ 5200 rpm.
The 2013 Buick Regal's engine produces 182 hp @ 6700 rpm.
The 2012 Buick Regal's engine produces 182 hp @ 6700 rpm.
The 2014 Buick Regal's engine produces 259 hp @ 5300 rpm.
The 2003 Buick Regal's engine produces 200 hp @ 5200 rpm.
The 2004 Buick Regal's engine produces 200 hp @ 5200 rpm.
I don't believe a 1998 Regal, regardless of engine, will have a distributor. It will have an electronic ignition that outperforms any distributor of old.
The Enclave. The Buick Enclave has 275 horsepower and the Buick Regal has 195 horsepower. The Buick T-type had a turbo charged V-6 rated at 325 vHorsepower.
The 2001 Buick Regal has a V6 engine.
The 2004 Buick Regal has a V6 engine.