I got a MS III (the best so far with 10x the timing resolution) for 350 bucks. I'm installing in my (soon to be) turbo E30. You can also find MS-1 systems for less than 200 that control both fuel and timing for NA or boosted motors. You can't find any stand alone ECU at triple that price with anything close to the features and support of an MS. The software is open-source, so plenty of people are programing configurations and add ons, such as individual coil fire, coil packs, knock sensor input, nitrous control (min rpm, new timing map or fixed retard), water injection control, real time barometric correction (for guys like me who travel) and plenty more.
You can use the built in map sensor for NA or boosted engines up to 21psi or you can use a modern hot wire MAF. Plus you can modify and DL nearly any configuration and flash it to the MS ECU after it's in. It really can't be beat.
Although the use of any standalone, more specifically replacing and/or the modification of factory related equipment in emissions controlled areas can be illegal and may make your car fail local testing. Forcing you to revert back to stock anyway, check your local laws.
This is very frustrating, in spite the fact a well tuned fuel and spark map on an aftermarket ECU can actually have your car run cleaner and more efficient than the stock ECU, it's still illegal. As an example, cold air intakes and open element air filters can actually fail you for emissions and inspection testing if your car comes stock with a thermostatically controlled air intake (heat riser off the exhaust manifold).
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.