My father was in the detailing business. check what the do for the price before you jump in . For my father $120 dollars got you
undercarriage steam cleaned
and a bunch more I can't remeber
Can you do this on your own yes . But for $20 I wouldn't do it. If your not sure how good a detailing place is check the cars that are already done. You will se the quality of work they have and base your conclusion on that. You only need to get your car detailed once in a blue moon as long as you know how to maintain it.
2001 Bonneville SSEI.
Engine: GEN V M90, ZZP 3.4 MPS, Intense S1X Cam, LS1 TB, SS autochrome headers, ZZP UD WP, DHP Powertuner, 3.29 Gears & DIY Shift kit