[ho_grayson]

i got 08 e90 335i. i have 3 questions

1: i plan to get upgrades above. what i heard was, i dont get much hp increase without ecu chip(jb3, proceed). only gain is just loud sound and bit more flow but very bad gas consumption. i dont know if it's true or not. is stock 335i exhaust one piece? do i need to cut stock exhaust if i get all above upgrades?

2: what's different between oil cooler and inter cooler? which one is more critical to performance?

3: how to pick good used kw v2/3? by only looking no oil leak?