And let's not forget, a modified car will appeal more to thieves who can strip it for parts, and also, the extra money you spend on the car has to be insured too.

Ha ha, don't worry about my right foot, it barely touches the accelerator on anything other than an uphill stretch.
I think the only way you could modify my Hyundai i20 to make it more appealing to theives (or in fact, anyone) would be to to disguise it to look like any other make and model...
My version sold only 400 cars in 3 years, and we think nearly all of those were with the 1.4 not 1.1 diesel engine!