Dude, put in some Gunk engine cleaner nad follow the directions, then run Castrol Synthetic blend 20w-50 oil and substitute two quarts with Lucas oil stabilizer. Should do the trick for your lifters - at least temporarily. But I think there is a thread on Dweeb telling you how to tighten your lifters to correct this problem - do a search there (Sorry Serg, not promo-ing another site, just pointing him in a direction to alleviate a problem).
As far as #5 goes, that light with briefly flash just to let you know that the trailer lights are operational, as in, there is no short in the wiring. When it doesn't flash, worry that your trailer's lights are not working - but if you don't use a trailer, don't worry about it.
Cheapest way to lift a Disco?? Depends what you want to do with it. Do you want to put bigger tires? For what purpose? Anything more than 2" you are asking for a heapload of trouble in castor angles, driveline issues, loss of power. If I were you, call John at 4x4ag (one of the sponsors of this site) or call Jason at Red Rhino. Tell them you want a 2" lift and they will set you up. If you check around on prices, call them back to give them a chance to at least match that other price. The lift is easy to do - OME springs and shocks might be the cheapest way to go. We can talk you through it. Your Bilsteins should be fine right now, but I guarantee you will want OME shocks to match your OME springs.
The best thing to do after your lift is to change out the driveline and get rid of the rubber coupling - ask John at 4x4ag about this. He will give you step by step instructions.
Anymore questions or need instructions on something, just ask or feel free to PM me.
Oh yeah, about that cute sister.....
