Been a few years since we tried these pipes out and since then we have learned a great deal about tunning scooters with 70cc kits and exhaust. We recently installed one on a Keeway Mtrix we upgraded with Stage 6 Pro 70cc kit and the results were great I must say not what I expected. The low end was great and plenty of 50mph speed and 10500RPMs no problem. Now we did use a 19mm carb which we now know did the trick along with Doppler Air Filter. The CVT was also tuned with Stage 6 clutch and bell along with MRP Ninja 4gram weights, what we got we like and will suggest to all.
When doing upgrades to your two stroke scooter all areas must be considered. The exhaust is not the only part needed to be added. An air filter plus jets are the least needed. A new carb with air filter is suggested. Along with these roller weights and strong belt that does not slip then torque spring then upgrade clutch and clutch bell. The CVT parts should never be ignored many a time we have simply changed the weights to achieve what was needed.