Unless you buy a slow CF card, most will be faster than the GVP bus.
Sure, you can buy SCSI to IDE adapters for 80 euros and up, but why would you do that when you can buy lots of different kinds for $40 USD or less? The most common kind I have, for instance, is the Acard 7726Q. The SCSI side is 160 MB/sec UltraWide SCSI and it won't work with narrow or non-Ultra SCSI unless you get a wide single-ended terminator and a wide-to-narrow adapter. But getting these still gives you a price that's much less than 80 euro.