well f these guys i had the same idea with my truck and i think its a good one...what i thought of differently was a couple things 1 dont try to fit 2 under the seats...do a front to back custom center consle if he's good he can make cup holders and a cubby space just like stock..and put all 4 in there either downfiring or out the sides if u trust people to not hit them , then instead of finding 2 more stock buckets look into jegs or somthin like them and either get nice racing seats (not expensive u can actully puy a pair from a checkers auto parts for 179...where i live ne ways) or u can find some nice tamed down racing seats the might be a bit more comfortable..anyways hope that helps some and good luck! if not why not just stick to 2 12 ??