acceptable fuel mileage? When my car was mostly stock, it would easily get 20 mpg around town and as high as 28 mpg on trips. Can 4.6's get that mileage? (I'm seriously asking, because I don't know).
As for durability, with the exception of transmission problems, I haven't had any durability problems. Granted, I only drive it about to work about 3-5 times per month. I'd drive it more often, but I don't trust the other driver's in the bumper-to-bumper traffic I sit in.
My SC has over 120k miles on it. However, I will admit the front suspension only has about 40k (rebuilt while swapping spindles for 13" rotor upgrade) and the engine only about 15k (rebuilt after blowing both head gaskets and breaking the ring lands on a piston while drag racing at the track.
Anyway, my point is, I don't think the SC is any less reliable than any other 12-18 year old car....they all need maintenance and a lot of them never got regular service during the years.
Yes the 4.6 can get that mileage, and better. When I had my 94 4.6 cougar, I got a best of 31mpg highway on a trip from north carolina to NJ. It would usually get between 27-29mpg highway.
The SCs aren't bad if you keep up on the maintenance, and you can do all the work yourself, including diagnosing drivability problems. I have had my 89XR7 for a little over a year now, and in that time I have put over 20K miles on it, and the only down time it saw was a few days when I did a clutch and motor mounts in it, so it has been pretty good to me. I have had more problems with it though, but they were all little things that were pretty cheap to fix. I've had to rebuild front suspension, replace the shifter, DIS module (was causing intermittent misfire), leaking valve cover gasket (passenger side luckily), a couple coolant leaks, multiple vacuum leaks, washer fluid hoses leaking, and I had to replace the MAF. Of all those things, the only one that cost me any real money was the clutch and motor mounts, and none of them have ever left me stranded in the car, so they were more of an annoyance than anything else. Doing the work on the car myself, I haven't had to put much money into it, but if I had to pay someone to do all the stuff I've done to my car (including diagnosing the DIS module, MAF sensor, and vacuum leaks, all of which caused similar drivability problems) then I would have spent a lot of money, and probably had quite a bit of down time. If you can do all the work on the car yourself, then they are great. If you can't, get something else. On the bright side though, if you can keep an SC running good, you can work on anything, so they are great cars to learn a lot on.
-91 Cougar LS, coming soon, complete overhaul
with a 427" Windsor.
-90 XR7 5-speed black on black w/sunroof, MP2, coated rotors, double intercooler, 15%OD, ported heads, comp stage 1 cam, 85mm TB, 90MM LMAF, 80# injectors, and ported big valve heads
-98 Mark VIII LSC, Procharger P600b, TR3650 swap and 3.73s.
-90 SC Automatic rustbucket winter beater
-97 Tbird Sport 4.6 Nice weather daily driver
-"Your buddy Mike is INSANE!" -ClintD's dad