Is there a thing as too much HP's?

[Andy]

Can horsepower be possessive... 'cause plural doesn't include the ' or the s.

...and no, there's no such thing as too much... just the wrong application of it. Perhaps there should be driver requirements for anything over 300, just like there should be for supersport motorcycles.

"Forming plurals of abbreviations

When forming plurals of abbreviated forms:

Form the plural with a lowercase s (never an es).
PBXs (not PBXes)

If the abbreviation contains internal punctuation, form the plural
with an apostrophe s.
Ph.D.'s
M.C.S.'s
(but CPUs, LANs)

Avoiding periods in abbreviated forms.

I mixed up my rules a little though HP's is still acceptable. HPs is preferred. Now we know. Thanks, Jackass.