Hi James, I can't comment on the pro's or cons of the upgrades, but I can offer something which may be of interest. I have a K series 1.8 165bhp (Caterham claim) 160bhp (Dave Adams of DVA expects is real) engine that I am looking to upgrade (sell). I'm currently getting quotes and setting up a convenient time to convert by vehicle to a 2.0ltr Duratec. As you can imagine this will mean a complete exchange. The engine is "SuperSport R" specification and was fitted by Caterham at a cost of £5,300 (I have all the receipts and invoices) It has covered around 18k miles and has throttle bodies, R500 exhaust and is managed by a Caterham MBE R300 ECU. If you are interested in a transplant for your vehicle let me know and we can discuss possibilities, timing etc... Regards, Sam.