I have had an impuse for the last 4 years its a great marker and it has the following upgrades brass hammer,cp on/off,cp vert reg, eclipse valve,smartparts lpr, backheart board, eclipse derlin bolt and the eclipse mag trigger.
At the end of the day the design is over 4 years old it to heavy and unless the upgrades your talking about include a new board it only shoots in semi (it may not even have a vison eye).
The ion is light has vison and will ramp at 17bps out of the box. Personally I would go for an Ion and upgrade that when you get the money or just buy an upped ion for the same price as a new one on the classified adds in this forum.