Also if there are any top brands toavoid would be nice to know
Considering
Continental SP2
Bridgestone potenza
Goodyear eagle F1 non-directional ones
Dunlop sport maxx or sp1s
Avon zz3
Of that list, the only one worth considering would be the Conti SportContact2. However, the Conti SportContact3 has been out for quite a while now, so someone is trying to flog you old stock. The SportContact3 seems to have a slightly softer compound than the CSC2, and so might address some of the low speed ride harshess.
Bridgestone Potenza = leave it in the garage when it rains!
Goodyear F1 = not tried the new non-directional ones, but their GSD3 was not particularly good for the twisties (fine on arrow straight autobahns and US freeways - which it was developed for

)
Dunlop SportMaxx = a poor tyre, though shockingly, I have to admit, considerably better than Pirelli P-Zero Rosso, which are truely fcuk-tastically bollox! Going back to the SportMaxx, it suffers from static deformation, due to a relatively weak carcass, and makes up for it with a relatively hard tread compound. The SP1 are the same carcass as the SportMaxx but with a slightly different tread pattern (but same hard compound) - so I still wouldn't recommend them.
Avon ZZ3 = never used any of the later Avons, but reports from others suggest they are quite good, but wear quickly. Avon make superb motorcycle tyres, and the older Avon car tyres I used to use were better than the equivalent Pirelli or Firestones.
As others have already stated - the best tyre, without any doubts, is the Michelin Pilot Sport PS2. However, these are
extremely grippy, and if your driving style is less Michael Schumacher, and more Michael Parkinson, then the Michelin Pilot Exalto PE2 might be a slightly better tyre.
Finally, yes, they do need to be the XL, or ExtraLoad type.