my little brother is picking up an 05 tsx (because I wont sell him my 04), and I was going thinking about items we should replace off the bat since the previous owner records are non-existant...

I was going to start with;

oil/filter
air filter
MT fluid
coolant
spark plugs

brake fluid looks decent...PS will get taken care of in the recall...

the clutch hydraulics are sealed, so no maintenance, right?

Anything else you'd do?

 

The replacement of spark plugs is only by mileage - 105,000 mi - there is no time period. So I wouldn't change spark plugs until 105,000 mi unless there is some performance problem. If you have to remove the plugs to look at their condition, you might as well replace them at the same time.

The cabin air filter can get very dirty sooner than the specified maintenance interval - I change once a year regardless of mileage - and I seem to find it fairly dirty each time.

Clutch fluid is subject to the same environment as brake fluid - but does not contain expensive parts. The brake system ABS/VSA is an expensive part to replace and can get corroded by old brake fluid - so changing brake fluid is a good idea at "severe" service intervals.

 

I would add cabin filter and brake fluid. You there's no real "test" for the brake fluid (and certainly not by looking at it), so you should change it. It's another maintenance item that's dictated by time not mileage (and it's overdue if it hasn't been changed before since it should be changed every three years). The plugs are supposed to be good till 110K (according to my 05 owner's manual), and were actually still pretty good when I changed them in my 05. These cars don't require a ton of maintenance, but in my opinion whatever is recommended, it should be done when called for. And a little more, a little earlier or more often, wouldn't hurt.