Hi to all, i need some help with the theory behind this conversion. Background: i currently have a '96 E220 convertible, it has the m111 2.2 engine with 4speed auto box. (on a side note it has: Jenhert install, exhaust system, wald bodykit, new wings, full paintjob/rust removal, minor engine work, remote engine start/uprated alarm, Bilstein b12 suspension, remote boot release, front fogs, and im sure a few other bits i forgot) The aim I want to change the engine for a m111 2.3L komp engine (post 2000) from possibly a clk or something similar. Then to this engine i will install the asp racing pulley kit, taking it to around 240bhp. The issue I was speaking about this conversion with the mechanic and he (and now i) are wondering whether the ecu (from the donor) will cause any immobilastion issues. We are in disagreement here, he thinks that the ecu will effectively immobilise the engine because it will require the key from the donor. I dont think that it will cause a problem personally, but then again hes a professional with 20year with merc under his belt and im not really, lol. I was assuming that i would only really have to have the engine, wiring loom, ecu. Also would the 4sp autobox be ok for this setup? i understand that the 4sp box is stronger than the 5speed but will it be good enough. also if i were to change it to the trip-tronic setup what would it involve. Many thanks in advance, ps. i will be posting pictures of both the cabriolet and the coupe soon. i am also planning a uprated intercooler system and brakes off a larger merc. i have not looked into the brakes properly yet, want to get the power sorted first.