Biggest/Cheapest easy tuning gains ?

[J4CKO]

I guess this must be up there, the Saab 9-3 TTid 130, starts out with 130 ish bhp and when this is applied,

http://en.bsr.se/products/t2094/

Hey Presto 213 bhp !

I guess its down to it being a 180 bhp Twin Turbo diesel, detuned as a marketing exercise down to 130 bhp but that must be a massively noticeable difference.

Love cheap (per bhp) easy solutions like that, like my mums old 85 bhp Rover 25, I had a BRM previously and sold it due to it having a failed headgasket, previous owner had been into bolt on mods and fitted a new throttle body along with other stuff like a "cold air feed" and new piggyback ECU, decat etc (all ammounted to nought as his cold air feed acted as a restrictor as he crushed one tube into another and it buckled causing a massive restriction), removing the cold air feed made a huge difference, then the HG let go, anyway, when it went I found the the original throttle body (he had replaced it with a bigger version), my dad stuck the BRM one onto the 25 and there was an instant upgrade from 85 bhp to 104 for free, the 85 just had part of its throttle blanked off.

Apparently a Mini one can be converted (engine wise) into a Cooper with purely a remap ?

Any others

[ManOpener]

Anything turbocharged will usually gain around 50+hp from a simple map, if the chip/mapping companies are accurate. For cheap big power gains, nitrous oxide is often a good choice. Most engines can withstand a remarkably large nitrous oxide setup as long as they are installed and set up professionally. 100hp "wet" kits start at around £100 on the bay of thieves.