Welcome to the SiR Forum.
Nice ride, you've made some great progress from being a ED6 to what you have now.
Not feeling that big spoiler actually, I rather would see you had the EF9 SiR spoiler,
thats a little smaller

You should also try gettin the rear chin-spoiler for you bumper, but my guess is that you are trying to locate that.

And do you have any better pics of those Mugen replica side-skirts?
And were they made especially for the 88-91 Civic or are they from a later model Civic?
If you are looking for some EDM stuff for the EE9 dont hesitate to ask, we might be able to help you out there

Yes the EE9's were also made in Japan and then imported to The Netherlands.
We also know where they were made through the blue VIN plate, theres a code on it which tells us when and where it was made.
Heres an example what of VIN plate could look like for a EE9
JHM EE9 38 00 S2 00001
JHM= Japan Honda Motor Co Ltd.
EE8 / EE9= Type of chassis, EE8 being CRX EE9 the Civic
3= Transmission type (5-speed manual gearbox)
8= Type (no further info available on this number)
00= Just a code, no other info available
S= Place of build (S= Suzuka factory Japan)
2= Year of build (0=1988, 1=1989, 2=1990, 3=1991) (VTEC only S2 of S3)
00001= Serialnumber for the car