Like the OP, I too am looking to replace the stock Active Suspension on my 2001 Q45t. I do not want to greatly diminish the ride quality and characteristics of the car, so coilovers have never been an option for me. I see no reason to make my daily driver land yacht feel like a track car.
I purchased a full set of standard RS*R springs and KYB SR Special shocks. I sourced them from Yahoo Auction Japan and used From-Japan as the auction & shipping proxy service. Stiffer RS*R and Espilar springs were also available specifically for the FGY33.
KYB SR Special shocks (NSC6004 & NSG9069)
https://www.fromjapan.co.jp/en/auction/ ... _aucid_auc
RS*R Ti2000 front & rear springs (N183TD)
https://www.fromjapan.co.jp/en/auction/ ... _aucid_auc
RS*R front & rear springs (N183D)
https://www.fromjapan.co.jp/en/auction/ ... _aucid_auc
Espelir front & rear springs (ESN-149)
https://www.fromjapan.co.jp/en/auction/ ... _aucid_auc
For OEM parts I ordered from Infiniti Parts Deal:
https://www.infinitipartsdeal.com/parts ... m=401_A004
Here are some helpful links I found with information regarding shock and spring replacements for the Q45:
https://www.nicoclub.com/archives/q45-t ... truts.html
kyb-sr-special-installation-question-t529670.html
y33-suspension-dillema-please-help-t564 ... l#p6386812
If you have installed shocks and springs on your Q45 with Touring/Active Suspension, please chime in with any further details that may be helpful.