Sorry to chime in late, but I did NOT make that Towbar...
What I made was a bolt-on towbar
ADAPTER... This is the HF 'type' Towbar...
http://www.harborfreight.com/5000-l...tow-bar-94696.html#pr-header-back-to-top-link
I paid $50 bucks 15 years ago... now it runs $70 and with a 20% off coupon, its $56 dollars! HA! Rated at 5000 pounds it is PERFECT for our little cars! A few customer reviews said that when they towed their 4000 pound Jeeps they noticed a bit of wear on the hitch pin mounts after only a few hundred miles.
My towbar has pulled my car about 3000 miles and other X1/9s to OK and back, TWICE. Absolutely no wear or problems. The bottom line here is to purchase a towbar that is rated at TWICE the amount of weight you are pulling and you should have no problem.
This photo is from about 12 years ago when I needed to carry my wife in air conditioned comfort for a few hundred miles. Turned out to be the hottest day that year! The towbar does not appear that unattractive...
(The tires here are 50 series, 175's... 215/50s in the rear. Nice rake but a bit tooooo low!)
I built this adapter so I could leave the stock bumper in place and simply attach the Harbor Freight Towbar by installing or removing two pins... or by removing 4 bolts to take it off entirely. I built two... one went to OK with White Fang... not to be seen since. The adapter, trailer towing lights, and towbar will all fit in the rear trunk with room to spare! It can all be built, including the towbar, for about $100 bucks.
I used the 'pads' that came with the HF towbar as attaching points, and bolted them to my adapter.
Here is a foto of the MAIN attachment bracket using a 2 x 3 inch piece of angle iron, probably about 1/8th or 3/16th thick. I used Grade 8 bolts and Grade 5 washers and nuts.
Here is a 1:1 drawing that can be printed out on an 8 1/2" x 11" piece of paper. For a cross brace (which is NECESSARY) a 2" x 2" piece of angle iron or square stock will work great.
All of it could be welded together as well but I would drill and install ONE bolt at every intersection just to be safe. I have thought of possibly using aluminum for a crossbar, but don't know if I could trust it for wear. I would never think to use it for the adapter plates..
This adapter bolts to the TIE-DOWN tabs under the bumper shocks to PULL and STOP the car. Then it is bolted UP top the bottom of the aluminum bumper through the factory fog light holes. In this manner, along with the crossbar, the MAIN adapter plates which are bolted to the tie-downs are ridged (because of the crossbar and because they are bolted UP to the bumper...) so they will not bend left or right. The stress loads to TURN the car are now applied to only the bumper and crossbar and not the tie-downs.
Best to bolt it up LOOSELY first, then pull the adapter forward and tighten the the tabs to the tie-downs first, THEN tighten the bolts to the bumper. In this manner, the car is NEVER being pulled by the bumper... which is attached to its factory brackets by sliding them into a very thin channel. These bumpers are meant to be PUSHED upon, and not PULLED upon! NOTE this issue for TOWING a trailer below!
ALWAYS insert the ignition key and insure the wheels are free to turn. The key can be turned off once the steering wheel is unlocked, but the key MUST BE LEFT IN.
PLAN AHEAD when parking so that you have room to pull out by just going FORWARD, and not needing to un-hitch to back up or back out.
NEVER, NEVER, EVER attempt to back up with the car attached.
Note also that many folks have successfully pulled their cars by removing the bumper and attaching the towbar directly to the mounting brackets on the bumper shocks... It seems to work just fine... but I always think that they are made to be compressed, and not pulled. I dunno if its a worry or not, maybe others can chime in.
As far as
TOWING a trailer is concerned... some have successfully towed by simply bolting a Class I receiver to the bottom of the rear bumper but as stated above... this is dicey because of how the aluminum is affixed to its brackets. This illustration is probably the best...
But someone here also THROUGH-BOLTED his rear bumper to their brackets so it could not pull off, and then simply bolted up the Class I hitch under the bumper. There are several ways to hide or minimize the appearance of the bolt heads... but I feel this solution is a very cost effect and equally as strong a mount as any other.
Continue having FUN! Write for more details if needed.