Sanctions are definitely a concern, which is why a healthy amount of spares and weapons would have to be bought as part of the deal. A through evaluation would have to be made as to the viability of a Tornado force for the PAF, but on the surface level, the Tornado is ideal per capabilities while potentially being affordable on the front end. Long term it may face the whims of the European and American defense establishments, but the PAF has managed to operate the F-16 over these past 30 years. Worst case, we cannibalize the Tornados and operate them like the Iranians operate their Tomcats. If we can get a decent platform at an affordable price, and in only a few years time, it would fulfill our need and allow us to retire the mirages.
On a tonnage basis, 81 Tornados which can carry 9000 kg each, would match the entire PAF Mirage 3/5 fleet of 180 aircraft which can carry 4000 kg each. For reference, each JF-17 can carry a little over 3600 kg. So it would not be a stretch to retire the entire Mirage Fleet if we can acquire the Tornados.
http://www.deagel.com/Combat-Aircraft/Tornado-IDS_a000460001.aspx
http://www.deagel.com/Combat-Aircraft/Mirage-III_a000733001.aspx
http://www.deagel.com/Combat-Aircraft/FC-1_a000302001.aspx
As far as carrying special munitions, if the F-16s can be modified to carry them, then the Tornado can be adapted one way or another to carry them.
The Tornado is maintenance intensive, but as Oscar points out, the JH-7 is also Maintenance intensive. The JH-7 is also a type the PAF has not flown much in if at all, requiring 5 years (per Oscar) to become through familiar with. On the other hand, PAF probably has extensive knowledge operating the RSAF Tornados on behalf of Saudi Arabia over the last 30 years.
Ultimately it comes down to the weapons the PAF will have access to for its strike Aircraft. If the Tornados can be bought at a reasonable price and PAF can buy the Storm Shadow and other advanced munitions, it would be worth it. At the very least, If the PAF can integrate its own domestic munitions and Turkish Munitions, it would still be worth it. If not, the PAF should just get the J-10CE; which can carry 8000 kg or further develop the JH-7A, with china, which can currently carry around 6500 kg.
Source:
http://www.deagel.com/