It is only pressed on; so a big screw driver or pry bar removes it very easily. Alternate prying at opposite sides and it comes off after 2 or 3 cycles.
Mark strut body.
For Civic Si front struts, we mark the strut body 2.125" (for 06-11 Civic Si) above lowest part of spring perch, where the cutout on the spring perch is located. Do not cut lower than this to ensure proper holding of insert in housing. Cutting at 1.75" is too low. The cutters can walk down the tube (essentially threading the housing); so be very diligent to keep it straight for the first "scribe" line around the tube (don't use much pressure).
** Note: For 12+ Civic Si, we cut 2.000" above lowest part of spring perch. Civic EX/LX cut location may be different because of lower spring perch location can vary slightly (please measure yourself).
Choose proper cut-off tool.
We use 2 pipe cutters for our process. The first one (gray at right) scribes a perfectly even line around the circumference of the strut body because it has only 1 cutter and 2 rollers to keep it straight. The second one (red at left) does 99% of the cutting with 4 very sharp cutters and much better penetration capability than most small pipe cutters. It can be noted that you can do the entire job with a small pipe cutter, but it has to be big enough for the 2.0 OD of the strut housing... and then expect to spends some time and muscle to make it all the way through. We've also seen many other types of cutoff tools used, including cutoff disks, hacksaws, etc.... but nothing does a better job than a pipe cutter. The small one pictures is about $40, but you can get a cheap one at Harbor Freight for about $20. The big red one costs about $400 (it's almost 2 feet long), and it's worth every penny for us!
Scribe line with accurate pipe cutter
As indicated above, the smaller pipe cutter has 1 cutter and 2 rollers, which keeps it very straight for a good scribe line. The cut-off must be very even for the Koni RACE inserts because it makes welding much easier. The straightness of the cut for a Sport shock is not as important, but if you ever want to upgrade to the RACE shocks, the welder will have a much more difficult time with it.
Cut off top of housing on scribe line.
IMPORTANT!!!! The stock strut is gas-pressurized!!!! So, if you just cut it apart without consideration for how the gas will escape, then you will have a lap-full of shock oil all over you. Note that Koni's directions show that you should de-gas the shock by drilling a small hole in the bottom of the housing.
We do it differently in that we hold the strut at a 75 degree angle (or totally upright with piston facing upwards) and cut the top off without first drilling the hole at the bottom. This is ok because the shock's oil line at full extension is about 1" under the cut line; so we get away with it.... and it improves our efficiency. If you are concerned about this, please do drill the small de-gassing hole at the bottom while the shock is completely upside down as Koni recommends before cutting the top off the strut housings off!!!!! The amount of gas that escapes is about as much as you can hold in your mouth with cheeks fully blown up; so it's actually not that big of a deal.
Pour out residual oil.
When you remove the piston assembly, be careful because there is lots of oil both remaining in the housing and also in the piston you are removing. The piston assembly when you remove it is actually 2 parts, and the actual piston can be remove from it's piston housing (see left, bottom picture for all parts). The piston itself won't have any oil in it, the piston housing will have oil in it (pour it out), and the strut housing will also have oil in it (see pouring in picture). Find a good oil pan to hold the parts while they drain. When all is finished, the picture at bottom right is the parts you will have in your oil pan.
Finishing the job.
These housings are an example of what you will have left after you dispose of the piston, piston housing, and all the oil. Note that the top of the cut housing have been deburred and are very evenly cut. At this point, we drill a 1/2" hole in the bottom of the housing for the anchor bolt, serrated washer, and convex washer that Koni supplies with their 8641-1497SPORT insert.
We use a step drill bit (Unibit)because it is WAY easier, and you should use plenty of oil for the drill bit!!!!!! If you don't have a step drill bit, best method is to start with a small drill bit and work your way up front there. We also use a very long shank counterbore bit to debur the inside of the housing where we drill this lower hole. The bolt Koni provides is 12mm; so a 1/2" drill works just as well. Be sure to torque the bolt to the proper torque as Koni has provided (55 lb*ft as of 6/12/11). After all cutting, drilling, and deburring is complete, we thoroughly wash the housing with soap and water. Pre-owned housings are washed top to bottom with some effort to remove road grime.
This same hole is where the compression adjustment screw is located on the Double-Adjustable RACE Koni inserts. Both Koni RACE inserts do not use the lower anchor bolt to hold the insert in place; rather we weld on a threaded sleeve to the top of the housing and secure the RACE insert in place with a threaded "nut" at the top.
Put rubber boot on before inserting insert!
Tightening retaining bolt at base of Koni Sport inert.
Double-Adjustable RACE shock with compression adjuster at the bottom.
DONE IF YOU HAVE FIXED SPRINGS
If you have stock or fixed-type springs (like Eibach Prokit), then you are done.
The rear Koni Sport shocks require you reuse the stock bump stops and dustboots, but....
Just one thing to note: The Koni Sport shocks for your 06+ Civic require you to reuse your stock rear dust boots and bump stops. But, you'll notice that you cannot get them off because of a little steel sleeve at the top of the stock shocks. In order to get the bump stops and dust boots off the stock rear shocks, you have to drill out the little dimple on the steel sleeve. (See the picture at the right for the dimple already drilled out.) This is a pain, but some patience and oil will help you prevail. And try not to make much "smoke" when drilling...too much smoke is a sign that you are dulling your bit... so go slow and you will be rewarded with getting through it in about 30 seconds. Try not to drill into to the shock piston, but if you hit it slightly, it's not a big deal. Use a small open ended wrench to pry the steel sleeve off the top.
Lastly, the stock dust boot will fit onto the Koni shock with a little effort to get it down to the shock body (where it sits when installed), but you have to drill out the dust boot so that it fits on the larger-than-stock Koni piston. For the dust boot, use oil and very light pressure when drilling so you don't spin the steel "washer" part in the plastic "boot" of the dust boot.