the timing issue has been long discussed- and that's why the vafc hack is really only good for up to 10 psi ish on your average t3/t4... 250- whp range...
others run it higher, but IMO, its risky...
i can't find the document i was looking for.... basically, it talked about how even with the btm devices, you still run a risk, as it compensates for it.
if you can afford it, spring for a hondata. its REALLY worth the extra 200 bucks.