Can I substitute 合适 in place of 量身打造？ 5万元左右的经济型小车，无疑是为广大工薪阶层量身打造的代步车。

Costing roughly 50 thousand Yuan, a small, economical car is, without a doubt, the most suitable vehicle for the salaried classes

I think I could write 最合适的代步车 instead of 量身打造的代步车， is that correct?
As lots of the comments have said, Yes, you can make the substitution, but that probably doesn't mean that you should.

The context is obviously an advertisement. It has psychology meanings between the lines. Using words like "Only for you" meant to make the targeted audience felt that they are special.  Of course, we do not really think a 50K RMB car is ONLY made for a special one, neither a $100K customised Tesla, unless it's the so-called Golden Rolls Royce (2.85 billion RMB). But everyone wanted to feel like being THE ONE, and that's why you probably should not replace 量身打造 with 最合适的代步车.