throw the same amount of wisely spent money at an Impala SS as you throw at a GN, and it will wake right up.. keep in mind that when you get past the front mounted distributor and reverse flow cooling, and you are dealing with a regular old small block Chevy.
bolt on some headers and exhaust, 3.73 gears, and the HOT cam kit from GM and you'll have one hell of a beast that is still as docile and civilized as a stocker- with 2 more doors than a GN.
I disagree due to me and a friend of mine both have the Impalas and the Turbo buicks and more money spent with less results with the Impala SS. With the upgrades you mentioned you will spend about 3k and run maybe, maybe 8.90-9.30's in the 8th...And mine ran 9.55 bone stock! Now change heads with the cam, exhasust, gears still very little pickup unless you take it too the level of the usual ground thumping SBC and then its not the cruiser it was meant to be. I do agree they are different cars and I love them both but if you spent money on your Impala first you would find yourself saying that damn for the same cash I could be flying in the Buick:biggrin: