Elzbieta is right to ask her question. One would not say 'these shoes are too large for me'. 'Too large' sounds clumsy to the English ear and the correct idiomatic translation is 'These shoes are too big for me'....no argument - that's just the way it is and to use the translation here would simply mark one out as a non native speaker.
Ha. I mistype to instead of too and get the question wrong. Ahhh Duo...
Слишком emphazises it much more. Something like "too much", "over the top". If I heard someone saying that the shoes are слишком велики, I'd assume that the shoes are so big that they fall off their feet. It's not grammatically incorrect but something not really typical you use when you are talking about shoes.