Giodi VS Solido VS Hot Wheels
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Left/Solido     Center/HW     Right/Giodi
One thing to remember is that the Solido & Giodi were out in the early 90's and aren't made anymore. The HW version is better in some respects , but still isn't great, but then again, its only a $20 car. IMO, the Solido is the worst of the bunch. The details aren't great & there are big gaps down the parting lines, down the side of the car. The one thing different on the Solido versus the other two, is that it doesn't have the pop-up headlights. The Solidos trunk doesn't open either.
Engine detail depends on what you like . The HW & Giodi versions have some depth to the engine bay, but the Solido is just one piece of molded plastic(with some chrome). The HW engine has visable stacks, the other two have the air cleaners on.
The interior is the best on the HW (but thats not saying much). The Solido seats & center counsle are all one piece. The Giodi interior is ok, not too much details. 
Prices for the HW are usually around $20-25. The Giodi is usually $30+ & the Solido is around $20(Ebay).
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