Re: mk2 rs2000 - common problems?
Get one in good nick - and that will save you a lot of $$$.
As for common problems, the 3 main ones that I encountered were:
1) rust in the bulkhead (check by tipping water down the base of the windscreen and then checking driver's and passenger's footwells for water),
2) stripped nylon thread on the gear box (resulting in the shifter coming out when least expected)
3) noisy cam (due to oil spray bar clogging up from poor maintenance. Replacing cam is a head off job on the 2ltr)...
I found them very solid and depending on how you drive them will determine how quickly parts will go FUBAR before others. I never had a problem with the diff, but mates of mine were replacing them all the time from doing burnouts.
If you want an RS2000, get one of them, and not settle for anything less. I found it to be a far better package over a normal escort! Front guards are spot welded on, so you can't just "bolt" an RS front on another car.
As for finding one, keep looking on carpoint, the trading post, and other advertising venues.
The 2 door seems to be harder to find than the 4 door.
'67 Mustang V8 4sp... what fun to drive!