I have the greddy turbo kit on my RX-8 with E-manage ultimate and from what i've experienced so far is full of @#$&. So i am looking for a better substitute what are the alternatives, Cobb, Standalone or better Piggyback? Sorry if someone else asked this, but I couldn't find any info.

P.S. My RX8 is 192HP 5 speed MT

 

You should ask MazdaManiac since the low power-manual cars are a pretty messed up combination of what the american automatics and manuals are
I have some doubts about the ecu model you may have, the engine is the common 4 port but determining the ecu you should refer to when buying may be a problem.

 

go with the Cobb from mazdamaniac on here, its your best bet by far!

 

Works on the Euro 4-port, 5-speeds just fine.
On the JDM models, it's 50/50 on whether or not the ROM is supported and Cobb is not adding new ROMs at the moment, though that might change in a little while.