had a quick look at the specs Cubes........ 20-65-65-20 with .350" (8.9mm) valve lift seems relatively mild.....however this equates to approx 50 deg of overlap and 265 (20+65+180) duration which I think is actually abit more than stock cams (I don't know what standard cam specs are).
As a standard rule of thumb, if you increase duration, you generally increase overlap (definitely in single cam engines)......the advantage over having 2 cams is that you can retard the exhaust and give more separation between IN & Ex centres, giving you less overlap and widening your power band.
If you've played with the gears it may explain why you have some good useable power.
Hmmm........there is a test apparently to confirm whether the solenoid is stuffed.......just have to work out what it is
Are you referring to the intake & throttle body gaskets?.......most peeps seem to be going metal these days, got any contacts for a good price on metal gaskets?