How does a MegaSquirt compare to having my car ‘Chipped’?

It is possible to get many of the same performance benefits of the MegaSquirt by having your car chipped IF the tuner chipping your car has your car onsite and custom tunes the map for your specific configuration on a steady state/load bearing dyno.  If you are not the hands on type, or you don’t plan to EVER modify your car/engine again, then this is not a bad option.  If you do ever mod your car again it will likely need to be re-chipped, on a dyno by a qualified tuner, to get the maximum performance out of it.  If you simply send your ECU off to a chipping company who is supposed to load a map on your car, or buy a canned tune online to load on the chip yourself you’re likely not going to get the results you’re after.  In either case that tune/chip was NOT designed specifically for  your car on a dyno by a qualified tuner so you are simply not going to get the maximum performance possible out of the engine.  They simply can’t do it– they have to make a lot of assumptions with no scientific testing on YOUR car. 

However, if you really want to take control of things, if you do have plans to further modify your car and you don’t want to have to pay someone to rechip it every time you mod it, and if you are open to learning something in the process then by all means a standalone EMS is the way to go.  And there is no more powerful system per dollar spent than the MegaSquirt, in fact even with the affordable price out of the picture the MegaSquirt line of Engine Management Systems rival the featureset of many aftermarket ‘high dollar’ systems.  Particularly the MS3-Pro Stand Alone EMS.  We’re talking 100% of the functionality of many high-dollar systems, without the high-dollar price tag.