Its kinda unneccessary for most set-ups. I wouldn't think it'd hinder anything...did you ask them why they said that? I know Jeff Perrin was telling Chad to basically run a big MAF map to get your blow through set-up to work and just tune from there. So, idk. I think Chad just thought it'd be problematic....so, he kinda ducked it. Because of lack of time. I'm interested in hearing other opinions on why that'd be a limiting factor. Unless that tuner just meant if you change turbo housings you'd have to change the pipes around. I.E. run the older WRX/STI housings. Instead of running the LGT/08 WRX housing turbos.
378awhp/373wtq Custom Dom 3 & CBRD tuned 2006 STI.
"When in doubt...flat out" - Colin McRae