The Smart Carb and Lectron require you to find the correct taper needle that will work in your bike for all load and throttle applications. I think a better option is the STIC metering block for the stock Keihin. The STIC does a much better job of fuel atomization and faster transitional fueling while retaining the ability to adjust individual parts of the fuel curve with stock jets and needles. Each bike is different and requires fine tuning of the carb specifically for the application and rider.
I bought a STIC for my GG 327 big bore at the end of last year and it made a huge difference. I could tell a difference in starting, idle quality, throttle response and top end power.
My 327 was jetted well before I installed the STIC and I can honestly say this STIC made a noticeable difference across the board on my bike. I posted my results on Thumpertalk
https://thumpertalk.com/forums/topic...ad-stic-xc300/