trucks and car seats

I have a Silverado crew cab. we already have our infant carrier but we can get 40% off a convertible carseat at babies r us if we purchase it before Oct 1st so I'm trying to figure out which one to get.... I can already see that having baby in the middle is going to be hard to get them in and out with an infant carrier, its a long way to reach and I'm kinda short so I'll have to half climb in the truck to get the seat out every time... this will just get more difficult the heavier our baby gets but I'm determined to have it in the middle so that's not changing.... I had originally thought I wanted the Graco 4ever all in one convertible seat.... but then I came across one made by Safety First called the Grow and Go that I liked better...... but then I got to thinking about the side of the carseat being so deep, this will make it a pain to get baby in and out.... so I got to looking and there is a Diono Radian RXT that has low profile sides that look like they would make getting in and out so much easier.. but is it as safe as the others? we may not use the infant carrier long, so I want something good for little babies too. anyone have any experience with any of these seats in a truck? or any other suggestions?