I recomend you replaceing your stock Alt. with the GM (CS130).
Its a very good Alt that you can retrofit to anything. the power ranges anywhere from 90amp. to 130amp. stock. Just go to Autozano and pict up an CS130 to fit an 98 Chevy Suburban. It will about 100$ goto your elect. shop and tell them to retro fit it.
Iknow this works the best cause im an electerial rebuilder and this is the only way to go. some Cj's I have put twin Alt's for HD winches and 1 guy had a Texas Star sweet 16 (2000 Watt) CB amp. for that I had to install 4 D-4 batteries(trailor truck batteries) and (2) 200 amp alts. No prob after that!!!!!
We have done so much for so long with so little, That now we are qualified to do anything with nothing.........