In my own experiences, I haven't found voltage stabilizers to do much. Voltage regulation is handled quite well by your alternator's built-in IC regulator. In fact, even with high-speed data logging, you will find that the voltage is already very stable on a newer car with a solid electrical system. I have found that the high-quality Japanese grounding systems, such as the Sun Auto Hyper Ground system, actually do make power and can increase fuel economy. However, it seems that the older the car is, the greater the gains are. This could be because of an older car's electrical system degrading over time. I don't think you'll find very large gains from a voltage stabilizer or grounding kit system on your new(ish) Scion.
Single-Cam Engines Rule!
I own an '02 Mitsubishi Lancer ES and always been asked the same question, "why didn't you just buy an EVO with its 4G63 engine?" A friend of mine and fellow Lancer owner claims that single-cam engines build quicker turbo spool over twin-cam engines. Is this true?
-Alexander Morgan
Upland, CA
It's not so much single- vs. twin-cam, but how well the cylinder heads flow. There are multiple books written on the subject of cylinder head design, but to sum it up: your buddy is probably full of it and doesn't know shit from shinola. The truth is that modern engines with dual (or quad) variable camshafts can spool a turbo quicker while generating more top-end power than a single cam engine. Running more than one camshaft enables twin cam engines to fill the cylinders with more air (or boost), and run cleaner and more efficiently than ever before. That's a win-win situation for a twin-cam engine, if you ask me.