I have a si one on a r18 and it's fully secured from the bottom. I drilled the holes like the instructions said on the bottom.
I also did not need to cut out the exhaust section either.

 

Sorry. But you have the r18 version

(1) the SI version has a larger black diffuser area. Your lip has the smaller/shorter black diffuser area (look at the first pic I posted)
(2) When I mentioned "drilling holes" I meant directly/horizontally INTO the painted part of the rear bumper (not along the bottom side).
(3) Also, look directly above your exhaust cutout. It matches EXACTLY to the r18 version (bottom) in this pic:

Unless you can point out the part number you got, then i will stick with that you have the R18 version







hsnap:

 

wow nice info, ill have to look at the HFP rear in my garage and see what one i had on before the Mugen diffuser.

 

I thought I had a Si one this entire time. My car is now ruined!

 

:word:

 

for reference, here's my R18 lip on my R18 LX-S

 

so blight!

 

Wow, nice find bro

 

finally, the first thread that compares it side by side, I knew the SIs were always bigger on the black part, just could never tell people without the picture. Great job and very informative.

 

I assume that the 2 dr Si's rear look also has a bigger black diffuser?

 

Pretty sure the coupe ones have no difference.

 

Great info and pictures.
I wasn't sure if I got the right rear lip for my 08 sedan si but now I am glad it is.

 

im gonna be the first atomic blue with a si hfp rear. Custom painted ftw

 

I have a 08, will this fit my R18? Either of these lips?

 

damn good info here, didnt think it made any different between the si model and other model hfp rear lip.

 

wow, this is actually really good info!

I would have NEVER guessed Honda to change a part number for Si versus non-Si. I would presume that if it fits the body of both, why make two different parts?!

Kinda ticks me off cause you know there is some additional overhead cost in producing two distinct lips and if they would have just cranked them all off of the same machine, maybe the cost would be a bit less!

 

Si sedan rear hfp Can be mounted on non si sedans BUT it will not sit perfectly. It will look lower on the rear and lots of gaps on the side..

 

you've done this? pics plz :clapping:

 

tell us how did you end up with both lips?

 

could belong to a buddy?

 

Good comparison thread.

GroceryR18, you definitely have an R18 HFP rear. There is no question about it.

 

sorry to bring an old thread back to life, I have an r18 and wanted to clarify that the si hfp lip will no sit perfectly with an r18? I like the look of the si lip rather than the r18 lip but it seems that my only option is the r18.

 

Toward the end of my first post:

........... All in all, both are slightly different.
Question still lies if one who has an R18 install an SI version?
Answer is yes, but its not fully secured on the bottom side.


Hope this helps anyone looking for HFP Rears for sedans

 

I understand they are different and the non-SI will not fit properly with the SI version, BUT, does anyone know what needs to be done for the SI to fit properly on the non-SI? Bigger exhaust, etc? I do like the look of it more than the non-SI hfp rear lip. LMK

 

Only for the sake of someone still searching for the answer but yes a si will work on non si. You must drill holes in painted section of stock bumper for mounting. I was in light rear accident so I will be replacing mine but pic attached of current.