I have staggered 15x8 et0 and 15x8.5 et -6 Watanabe's on my NA. With Jubiride 40mm flares and 205/50 ku36.
I have no handling, guard or clearance issues with my setup but there are a few things you should know. I originally had 15x8 et -6 all around Work CR-01's ages ago but found that my old Autokonexion 30mm flares were too narrow to clear the wheels. I can constant rubbing issues and eventually a wheel bounced up and cracked a flare. FYI: you don't want that to happen.
It's a big commitment going flares. Once you cut the rears, there really is no going back so make your mind up whether you really want this. Once it's done, it's done for good.
The other thing is wheel size and Watanabe Type-R. If you do end up with Wat's, know this: Type-R WILL NOT fit over anything bigger than stock na6 brakes. Reason? The centres are semi flat like a lot of older Jap wheels, however it's the size of the hub face that becomes the problem. The the wheels hub faces stick out quite a fair way against the mounting face of the cars hub, this isn't a problem on an na6, but on na8 and so on, the front brake caliper bracket will touch the back of the wheel. This presents a massive problem. I measured up and on my fronts, I'd have to use a 13mm spacer to clear my na8 brakes. I switched back to na6 brakes for this reason. On CR.net you will see people who are running them. I've PM'd the guys and what they have done is taken the wheels to machine shops and had the back of the mounting face of the wheels milled back a few mm to stop interference with brakes. It's an expensive job and may compromise the strength of the wheels if not done properly. I chose not to for that reason.
Now I mentioned wheel size. A friend of mine has some 15x10 superlites on his n2 flared na. Unfortunately the guards aren't the problem. The wheel's actually knock against the inside of the wheel arch and hit the coilovers. This means he cannot get more than 3/4 lock in his car without banging against the inside of the guard (that is after sledge hammering the inside of the wheel arch for more room). I don't know the offset of the wheels but you can look it up, superlites only came in limited sizing and set offsets.
By all means run whatever you want in the rear, but remember that your front wheels have to turn. This could mean having to trim your bumper and hammer your guards, all sorts of things.
I'd stay away from running the 15x9 -13 in the front though. The reason being that if you intend on running bigger brakes, after spacers your total offset may be closer to 15x9 -26 in the front.
