From my little bit of experiences testing summit models regardless of stock or aftermarket exhaust/head packages.
1)*great clutch kit* stock engine
2)*great clutch kit* head
3)*great clutch kit* head n exhaust pipe (
complete package)
I keep a tally going in my shop of aftermarket stuff I see. I know the numbers of what my clutch kit is being married to for
i)customers
ii)guys who have a small perf shops on the sidelines
iii)dealers
They who install my clutch kits, (this is only my own tally of people I correspond with) there are more SLP pipe/head packages that go onto these sleds than all the other aftermarket put together.
Example heads, as of August 09 - 14 terra alps, 19 dynoport, 8 mots, 77 slp, 4 DnD...etc
One guy who works out of his garage in Lamont AB put 14 SLP packages on summits alone and married my clutch kit to it, never mind the other guys down in USA.
I have got to run some of these sleds, an 07xp(Joe is it an 07 or XP?
)in particular that just freakin flew (one of "drop the hammer" & "800HMX" setup sleds)
Getting a great head is well....just great.