Dump pipe for sure.
How much is 'little money'. If I had my time again I'd do the suspension first, such a difference and I didn't think it was too expensive (SK group buy).
Response from the standard turbo's generally can't be improved on that much, because they are designed for response. You could try all the little easy things like CAI with multiple intakes etc. But besides that your going to have to look at turbo upgrades and injectors etc. which start to get expensive quickly.