which is better na or turbo on a ka? faster? cost less? more reliable?

are you serious?

turbo!!!!!!!!!!! faster of course, reliable...all depends on how you tune, cost...well its more performcnce parts needed for turbo so yea its gonna cost. NA is gonna be more expensive to get a great amount of hp. The turbo may cost you 3g's but your hp gain will blow a 3g NA setup away.

With the KA, turbo is better in everyway, except maybe bling factor, but as the OSG car showed, you can have plenty of that with a KA-T.....so KA-T.