From this weekend's track day at US Air -
Had the track to himself for almost 2 hours at one point. The Aprilia didn't materialize.
He said the CRF150R (4-stroke) is faster than a similar CR85 (2-stroke). I expected they would be almost exactly the same.
We have done a few small mods to the CRF, but it's mostly stock. Last time at home we replaced the (weak) single-piston front caliper with a 450 dual-piston caliper - which helped a lot. Also removed the wire mesh inside the air filter frame and increased the Main Jet to compensate. All improvements so far.
Suspension is next on the list.