Disco 1 Lack of power

My 300tdi auto was off the road for almost a year following problems with the transmission. Having finally replaced the gearbox with an exchange unit from Ashcrofts I was looking forward to running the Disco again. However, I'm really disappointed with performance. I have a large Allisport intercooler + Ronbox fitted. The latter has been tested by the manufacturer and confirmed a working correctly. Previously, with the fuel setting on max I was getting a major leap in terms of performance but now there is no noticeable difference. So I need to check systematically what else could be at fault. Can I drive with the MAF disconnected or will this result in problems with the ECU. Same for the turbo boost sensor - can I safely disconnect it and test drive?