Massive can of worms here, but from what I've been told and learnt over the last few years is wide rims and wide tyres do not guarantee the power getting put down on the road
The car has got to stick close to stock offsets, widths and similar rolling radius' as possible for optimum handling
Simply the R&D of Toyota can't be matched for this car and chasis, regardless of power output, obviously there will be slight le-way where you may change one aspect which will in turn affect another suspension wise - but it would be that small that you would barely notice a difference to your track times or your feel
Slapping 11.5inch wheels - guaranteeing a 315minimum fitament is not the way you want to go if your looking to keep the stock handling - which tweaked properly is very very good
In Drag cases its completely different - go as wide as you can with a very soft spring rate rear and you will knock seconds off your 1/4mile but street driving will not be anything like the optimum with a setup like that
I used to want as wide a wheels as poss - I have now went from 19-18's to try to stick with stock offsets and RR's they car feels much more planted now and I get more grip even with a narrower tyre
The minimum tyre width b.t.w will be stock - 255 iirc - best go with stock U.S wheel width 9.5inch and a 265 or 275tyre
With a good setup Lexus GS300 Sport Rims will do also as they have a stock offset and come in anything up to a 10.5inch wheel, however the suspension will need setup for optimum handling and grip especially the wider you go
On the front you want to keep it staggered - 8.5inch wide wheel for optimum turn in anything wider you begin to tramline, theres pretty much no benefit to running wider on the front on the sup
Check out the car Bible its a very interesting read and something you dont want to believe at first - especially regarding contact patch - it defies rational logic
Car maintenance : Everything you need to know about wheels and tyres.
And to answer the initial question - stick with forged rims as you can have a very light cast wheel but it could break pretty easily, Volk RE30's are only 6.8Kg's a rim (18inch)
