It really depends. I ran kit for a long time about a year. However i tore apart my entire ka and freshed it up. Just a stock rebuild. I had the top mount kit (not sure if you got top mount or bottom mount). Too lazy to type a paragraph so imma make it quick and if you have any questions feel free to ask
Pros
-Kit fit all really well
-Customer service great
-Packaged well
-Ran great
-Drove the car all the way from Santa Clarita to Salt Lake City, Utah for business on 12lbs with no issues
-I DD the the car at 12lbs everyday and it was sex
Personal cons
-Exhaust mani started to crack and causing leaks(had to weld supports)
-Greddy "STYLE" BOV was giving me pms issues
-Diagram on wastegate blew causing me to over boost and eff up piston #2
Things i would recommend
-Do it right and take time while putting together
-Do a stock rebuild on your ka
-Dont reuse your head bolts as they stretch, get head studs
-Dont go over 12lbs
-As stated by someone else do something with your PCV (i blocked mine off and removed butterflies from intake manifold)
A couple other things i did
-370cc injectors
-Braided lines for oil feed and return
-Head studs
-Felpro gasket
-Bigger radiator
-Got a chip i had to solder into my ecu for the tune (forget name but it made a huge difference)
-255 walboro fuel pump
-Boost, Water Temp, Oil Pressure gauges
If i remember more i will add lol
All in all i was please with it for being my first boost project and something to learn from.I loved my KA-T.