i've driven a fairly worked 4k around for about a week or so (cam, carbie, compression, exhaust) and really there not all that great no offence to anyone that has one, lots of noise, lots of fuel, and you have to rev it to about 2500-3000 or else its flat and lumpy alright performance
drove a ke70 4age just last week and it would have shat all over the worked 4k with still having the fuel efficiency of a twin cam 1.6 4cyl, driving fairly hard i recon about 8 liters per 100ks
ze or te would be very cool, never driver a boosted 4age :)
all my gear is still in the shed as the boggie engine i got has the compression of a inflated bike tire