My 2 cents....So i first punch out all blocked holes and run an other 1000 kms, the improvement was really there but the hifax still tend to stick on cold weather trails, especially at the beginning of the day when there are few loose snow on the trail.
Then i fully clipped it , the better thing i made on this sled. The improvement was amazing, i was able to run in almost no loose snow condition (icy lakes) at decent speed without any trouble. The sled feel a lot less restriction when i slowed down and the gaz mileage was also improved. Ride 8000 kms last season and my last hifax set (eom) did 6500kms ( i killed them in terrible conditions on the last rides at spring).
A trusty guy i know fully clipped is 2005 RX1 track and see improvement in all condition including top end on radar run.
It make no sense in my mind to let rubber rub on the hifax. Rubber don't slip !!!! it just make friction and steal you HP ... It just make manufacturers put some $$$$ in their pockets (track cheaper and hifax sales).
bye
Alain