Direct Scan runs in DOS...so no blue screens or rebooting
Direct Scan captures up to 18 frames a second, Turbo Link goes thru the ALDL and only captures less than 1 frame per second.
Turbolink can be hooked up using the MAT sensor to monitor boost levels...DIrect Scan does not monitor/record boost at all, only the pulsewidths sent to the boost solenoid.
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They are both very easy to use. If just using for tuning, I have no preference....If using at the track, then Direct Scan all the way because on a 7 second blast thru the 1/8 mile, you will want more than 6 frames recorded for the run, alot can happen with the engine readings in 1.5 seconds that TL might miss, and DS 18 f/s will capture, as far as boost, I just watch my boost and KR gauge which are mounted side by side.