LS manual will fit np(no problem). You said ur head was built wat did u mean by that. You can get LS internals cheap, but GSR and ITR internals won't fit the LS pistons(or the crank). The best match is either B18B internals, b16 will fit too(11:1 PR3 more power) or all GSR internals with a GSR crank. For Vtec all u need is a RPM activated switch. The ls computer will run it but the stock rev limter must be brought up. GSR or ITR ecu is better for fuel maps.