The T25 turbo on the KA would be a little to small for the amount of displacement the KA has. It would work, but it wouldn't offer that much of a power gain as other turbos could. You could get something like a T3 turbo and then customize everything on it to your specs (compressor wheel, turbine wheel, turbine housing, compressor housing) and that way you can sorta decide how much power your going to get out of it. Or something like the HKS GT2835 turbo would work well on it. These turbo's will spool fast and offer moderate power for your car (200-300 whp). If you are wanting more power then you could just get a bigger turbo, but remember, the bigger the turbo you are getting the more lag you are going to have while your waiting for the power to kick in.
A T3/T4 turbo will be a good one if you are looking for power in the 250-400 whp range. This is a bigger turbo than the T25 and will require a longer amount of time to spool but you should have full boost by about 3700-4000 RPM. I wouldn't go much bigger of a turbo than the T3/T4 just because you will have to wait longer for it to spool and say that it didn't have full boost until about 5k RPM, then you've only got about another 1400 RPM or so until redline. So your spending most of your time spooling the turbo when with a littler one then you could have had boost a long time ago.
Good Luck