Tire/Wheel + mild drop help

[dalli]

Hey guys, I want to ask you guys from your experience. I am sort of in a dilemma.

Im deciding between:

xxr 527 18x8.75 + 35 all around with 225/235/40/18 Michelin AS3's

with pro kit springs(1 inch drop)

OR

xxr 527 17x8.25 + 25 all around with stock tires

with pro kit springs(1 inch drop)

(this is the cheaper route btw)

Question: With the 17 inch xxr with stock tires + 1 inch drop, how will this affect the tire grip in respect to stock height/rim? Will their be less grip?

I can live with stock tires from my experience now... I have driven in couple snow storms in the north east on stockies and I had NO SLIPPAGE except for when on local streets but that was manageable.(I also can take bus/train if too much snow outside)

I also driven the stock tires in -1 F weather back in December upstate NY and had no slippage except for when I stepped on the gas pedal from a stop sign.

[dalli]

Also what are the pro and cons

for xxr 527 17x 8.25 + 25 in rear and + 35 in front? Is the difference in offset considered a staggered set up?