There are two excellent choices for GR-Tornados in 1/72.
One is the Hasegawa kit, revieved
here! If you want lots of load, you will have to add ordnance from one of the Hasegawa Weapons Kits. This one has been released in several boxings, the plastic is the same and you might want to use aftermarket decals anyway.
The other one is the Revell kit, of which the ECR version is reviewed
here. The Revell kit contains all the load options that you could dream of and is very nicely moulded as well.
You can also read a comparison between Revell and Hasegawa
here. According to this analys none of them is perfect but I still think both are very nice kits!
When it comes to pricing, I think the Revell kit generally is quite a bit cheaper than the Hasegawa one. On the other hand, there seem to be lots of second hand Hasegawa kits changing hands for very little!
Finally, if you ever feel like building a fighter Tornado, remember that the Revell F3 isn't even close to the GR-variant when it comes to finesse, being a re-boxed Italeri kit!

Magnus