i was going through ebay and i came across some ecu upgrades..

http://cgi.ebay.com/ebaymotors/MUGEN...Q5fAccessories

and

http://cgi.ebay.com.au/15BHP-Power-M...item25593773c5


are they worth it? will they stuff up anything? also do they work with the stock ecu?

any help is much appreciated guys