Go aftermarket ECU and loom with coil on plug, it will be the best few grand you will spend. Just look at all the posts about "my car misfires" etc... The car may not produce more power (although I bet it does) but it will be livelier due to the better mapping. Then just lob on a Borg Warner EFR if you need more power and less lag but bear in mind it will kill a 4x4 box due to the high low down torque. Mark Shead at MAD did all mine and I am now finishing the new box and diffs to handle all the power (mine made 470bhp and 500lbft on a standard engine and would do more with better intercooler)