just did mine with ngk's...a;so did the ht leads and dizzy cap /rotor - stuff the plugs check your dizzy cap/ rotor i was AMAZED the car even ran with the condition of mine...seriously i had a slight (and i mean slight) wobble on the revs at idle (maybe 50 rpm on a bad day) changed the cap and wires, cleaned the throtle body - made a diff...ps I had changed the plugs a week before...

I've been using the Bosch Platinum +4's and like 'em. They've been in the car for quite a while now (2 yrs?) with no noticible wear or degradation. However, I agree with the earlier post your problem is likely sourced somewhere else, most likely intake.
--
Bob Kraushaar '94 945T, '91 940T(ret), '88 240, '84 242T, '94 F-150, '89 560 SL, '68 Shelby GT-500 KR

I have used Bosch platinum with good results. Re mileage, you might consider the fuel injectors (replace or clean), air filter, plug wires and coil. When I bought my used 960 I did all these, and vacuumed inside all hoses, replaced the fuel filter and flame trap ($2.50), and adjusted valve clearance. The year after I replaced the battery (roughly every 3-4 years) A 940 or 960 is still a heavy car, but these should make a difference. Next I plan to replace all fluids with synthetic. Much of this the novice mechanic can do to save the expense. Hope this helps.

Bosch Super copper plugs (WR7DC? if I remember right) will work correctly.
If the car's down on mileage you should check the big turbo air hoses for any leaks- vacuum leaks in a turbo cause a very lean idle, then VERY rich conditions upon acceleration. Fuel mileage will suffer drastically from even a small leak.
The plugs themselves will have little impact unless the old ones are so burnt or fouled that it's misfiring.
--
Rob Bareiss, New London CT ::: "Roterande Fläkt Och Drivremmar!"

Not sure but I hope it's Bosch Platinum #4216...just got them.
--
Tom F '95 945, lein holder on a '95-944Ti, & RIP '78-245