The V8 will definitely give you that performance that you are looking for, but it still won't respond or drive like your 300hp coupe sports car...that is just the nature of SUVs that aren't sport-tuned. But a V8 sets you back +$1500 over the V6, so that is something to consider. I'm willing to bet you will like the V8 better than hte V6 on your test drive.
I went with the V6 and I feel that the engine smoothness and response matured after the first 1000 miles I put on it and I personally am satisfied with the driving experience. My Lexus IS300 still drives smoother and sportier, but I didn't really expect the same driving experience from a heavy SUV.
I paid around $36k for my Laredo X (4wd, V6), but I've seen people get around $34K-$35K for it based on their discounts/deals. If you want the V8, add $1500 on to that. If you are a member of Tread Lightly ($60 for 3 years, I believe) you automatically would get 1% below invoice price with is a really good place to start.
2012 Laredo X : QTII, 430N nav, true blue pearl