I always grew up rinsing the underside of the cars as part of the prewash to at least get some of the grime and debris out. Is this really necessary or a bit of overkill (as if that exists in this sub-forum haha)? I've become lax about it with the s2000 because it's low and harder to get a good angle to spray some areas. I've never noticed an undercarriage wash in any of the detail write-ups that I've seen either.

Point/question 2: I have the Cusco ladder/suspension bars underneath and the Spoon polished lower rear bar. Do people clean/wipe these down? I have a very stock-looking car right now, but I always think that shiny bars underneath would be a nice hint of added performance or whatever you want to call it. I've only wiped down the bars when it's on the rack getting some work done, but it's been a while since I've done any work where it needed to be on a lift.

I thought about using the same Eagle One never-dull metal polish that I use on the exhaust tips to do the spoon bar, but I was wondering who else takes time to clean up the underside?

 

I routinely clean the underside of my cars, none are driven in the rain so the only debris is dust/road grime. I have access to a lift which makes the cleaning process easier, but you can can do a similar job with just jack stands.

 

routine as in the weekly wash, or routine as in whenever you wax (every month or so)?

 

Every time I wash, since they only have dust, a simple wipe down over already waxed/polished surfaces is needed. Also, these are not daily drivers which makes their up keep far easier.