The LS1 will out run the LT1 with the mods u listed, on top end anyways......you need a bigger cam and a set of heads if you wanna make power. The LT1 makes awesome TQ and makes it early, but the HP drops off too soon, you just need more mods.

here ya go, they charge flat rate tuning and use LT1 edit.

http://atlpf.com/