The megasquirt is a good system, but I'm not sure you guys realize how much work you'd be getting into installing a megasquirt system.
DIYAutoTune.com Megasquirt Kits / Assembled Engine Management Systems, Wideband o2 Sensor Systems and tuning products
Browse around the site, read everything you can, they even let you download the software. Crack it open, see if it's really what you want.
It sounds like you guys read too much into that ONE blog article about how a Greddy emanage was blamed for blowing up a lexus - how many engines do you think megasquirt is "responsible" for destroying (or was it user error...)? If you're doing something stupid it doesn't matter if its a piggyback like an SAFC or a $$$ Motec standalone.
Standalone's are awesome, but have you ever used one? Not all of them are very user friendly. I'm not saying don't buy the megasquirt, hydra, AEM, Haltech, ect. I'm saying know why you're buying it.
Before you decide please consider reading through Pressure's posts on his 5SFTE powered celica.
6G Celicas Forums > How to Turbo your 5S-FE
and here:
300rwhp 5sfte
and read mrturrari's smt-6 install:
93 5sfe - SMT6 installed and working
For what it's worth, I like the emanage blue so far, it's done everything I've asked it too. No it's not perfect, but it fits my current goals for my car.