well, I don't know if I'd agree with the last line about costing the same as a 190hp car. The TII is 160-170whp and with ~1200 bux you can make 300HP (BNR turbo, accompanying fuel and electronics). You can add another 1200 if you want to use a standalone. LIke you said, we're talking older technology, maybe that's what makes the differences in prices.
As far as sequentials:
I thought it might help with the top end. I see that the Greddy upgrade in your charts has great low end that tapers off after 6K RPMs in one graph and 7.5K RPMs in the other. Wouldn't a second turbo maintain linear power all the way through the powerband? Similar to the FD setup?
