Oh,sorry, i didnt understand you right! I did not do any modifications with engine. The modifications were made with exhaust(stock gsxrs exhaust was remade) and powercommander was installed. What about the engine i dont think that any modifications should be done with this bike because it is very,very fast in stock and any modifications as a new exhaust, powercommander is a waste of time and money- as a result we have big Fuel consumption and 0,1 second faster for 1/4 mile, you understand this only after many years of work with your bike - nothing is better than stock! If you want good results in 1/4 mile the bike should be fully remade : suspension(lowering), engine(with turbo installing and nitrous oxide) , exhaust(installing good quality full system exhaust) ,extending of Motorcycle pendulum( to make the contact of the road and bike better)- this is not only one 10000 dollars.